Rivista Itaiìena di Paleontologia e Stratigrafia BRACKISH MARSH BENTHIC MICROFAUNA AND PALEOENVIRONMENTAL CHANGES DURING THE LAST 6.000 YEARS ON THE COASTAL PLAIN OF MARATHON (SE GREECE) MARIA V TRIANTAPHYLLOU" KOSMAS PAVLOPOULOS" THEODORA TSOUROU' & MICHAEL D. DERMITZAKIS' Recei'-ed Apríl 23, 2AA2; acceptecl Januatl 22, 2003 | 1pr l;;,' Key uords: benthic foraminifers, ostracodes, microfaunal bio- topes, marsh paleoenvironments, Holocene, Marathon plain. Abs*act. The present 5ssi1., based mainly on rhe analysis of toraminifers and ostracodes, provides evidence of paleoenvironmen- tal changes on the coastal plain of Marathon (E. Greece) during rhe last 6.000 vrs. Three sedirnentary units lagoonal formatìons - were recog- nized and identified as A, B and C. They range in time bers.een be- fore 55OOBP - 3500Bq 3500BP-25008P and 25OOBP- recenr, respec- tiveiv The study of the brackìsh marsh microfauna of the Marathon plain Holocene sediments reveals the presence, durine the last 55OO )'rs, of three distinct biofacies in the sedin-rentary units alre:dy e:- tablished. Alternating mesohaline - oligohaline (MO), oligohaline - fresh water (OFV) and mesohaljne - oligohaline to olieohaline - fresh water (MO-OF\í) biofacies in the framework of the sedi- mentary units indicate a general trend iandnard along the plain sug- gesting a slowìng of sea-level rise probabll. correlated with a relevant tectonic uplift. One prominent feature of this study is the clarification of the ecological preference of the species Tricholrya/us aguayoi (Bermudez, 1935), which is dominant in oligohaline conditions under an influence of fresh $'ater input (salinity less than 15 %,). Riassunto. Questo studio è basato soprattutto sull'analisi dj fc- raminiferì ed ostracodi e consente di valutare le variazioni ambienrali durante gli ultimi 6.000 anni-nella pianura costiera di Maratona (Grecìa). Sono state distinte tre unità sedimentarie di ambiente lagunare, definite A, B, e C, che si dìstribuiscono ln tem- po tra 55008P - 350088 3500BP-2500BP and 250OBP-Arruale, risperrir amente. I-o studio della microfauna del- la palude salmastra nei sedimenti olo- cenìci di Maratona rivela la presenza di tre biofacies alf interno delle tre unità sedimentarie precedetentemente stabi- lite. Iialternanza di biofacies mesoha- line - oligohaline (MO), oligohaline - acqua dolce (OFV) e da mesohaline - oligohaline a oligohaline - acqua dol- ce (MO-OFV), nel contesto delle tre unità sedìmentarie, indica la tendenza verso I'incremento dell'area emersa del- la piana, ottenuta mediante un rallen- tamento dell'innalzamento del livello del nr:re colhgaru con urr signi[icari- vo soller.amento strutturale. lJn aspet- to irnportante di questo studio è I'indi- v:iduazione delle preferenze ecologìche del foraminifero Tricbohyalus aguayoi (Bermudez, 1935), che domina nelle condizioni oligohaline sotto l'influen- za di apporti di acqua dolce (salinìtà inferìore al 15 %").trio - Topographic map showing the location oI trenches (1,4,10,1 1) and boreholes (6,2). 1 Universitv of Athens, Dept. of Geologv, Section of Historical Geologv-Paleontology, Panepistimiopolis 15784, Athens, Greece E-mail: mtriant(qì geol.uoa. gr 2 Harokopio Universitl., Faculty of Geographl., Z0 El.Venizelou Str., 1761, Athens, Greece. 510 M.V Triantaphyllou, K. Par-,lopoulos, T. Tsourou e. M. D. Dermitzakis Stratigraphic correlation of the boreholes and trenches studied, location of the samples analyzed and position of sedimentary units and biofacies (MO:rresohaline-oligohaline, OFW:oligohaline-fresh water, MO-O\WF:mesohaline-oligohaline to oligohaline- fresh water). Legend: 1. Artificial fill, 2. Topsoil, 3. Sand, 4. Sand with gravels and pebbles, 5. Silt, 6. Clay, 7. Silty sand, 8. Sandy silt, 9. Clayey silt, 1 0. Sandy clay, 1 i . Siltv clay, 12. Sandy clay with sub-rounded gravels, 13. Palustrine mud, 14. Lagoonal mud,1 5. Peloidal algal mud, 1 6. Mudcracks, 12. Rootlets, 18. Charophytes, 19. Pellets,20. Gastropods, Bivalves,21. Bioturbation,22.Pert,23. Algal pear,24. Hard ho- rizon. Peat ages are calìbrated (in yr. B.P). Trench I 2.O ?.p c) E -c .C .a C) I |,0 Trench 4 Trench I0 Borehole ó Borehole 7 t8-7 T8-ó T8-5 T8-l Mo tg-2 Tl 0- t1 Il 0-4 TII-I borren borren Unit C 24008P-preseni Unii B 3500-2400 BP Unit A before 5500-3500 BP 4..- ró_P.l.l Tó.PIA' t6-P2A tvo tvo Tó-Fossl T7-5 TEGEND ffifl W E!.E!@ Fri:Íl t:111"Í.:....'] r-----l ]_ t:iii:ii:il Fnnnl f:: i:::i:: ì r Flq'' E ? l-----1rn ? f ::-:t i l ffia-- - L-.:-:-l- ^ v, F.__ltr, , I--:-t-|. o, F-.:-r-rl t4, a Fro EEEE ffi I ffi lîl:lT1 17. 18, 19, 20. 21 . 22, 23, Fic -\bsolùte Sample Altitutc (m) 0.25 -1.33 -2.00 -2.33 TRN.JCH ] Tl-l 1.30 BOREI]OLE 6 T6-PÌB -1.29 T6-PIA -r..1 2.12 T6-P2A -1.53 2.62 T6-FOSS1 2.20 3.20 BORIHOLE 7 T7-9 T7-8 T7-l TRENCII .1 T8-7 T8-ó T8-5 T8-3 T8-4 T8-1 rg-z TRENCH ii) Tl0-l T10-3 T10-4 Tl0-5 TRENCH I 1 sih) p.al contaìnrng teuestrial gastfopods, charoph)tcs and tòramÌn'1èral tìagments. Pcllclcd mud containing nmlluscs. :.,rJ) .1.) ..'r'r' ' ': .l'.'r.plIr:.. Dcpth (m, Sedimcnî description , , n : ' rJ1 clJr , rr :rrnin: j(11 rrrr fiegnlenls and gàstropods. palc J'.cllow (-5Y V8i C2) Palusbine nNd contaming charophytes olivehfo$n(2.5Y q!4g!!qsp4!- v,1rc2) Color Units (\4unsell\crlct broracres J,t;i',""T:j:ì, dark grai l2.5 Y, I ) bafren ""*llìlì1"' oF\\ gfa) (5Y VsiCì) l\lo oFw gastropods eild bi\ilvcs L2l Pallrstdne mud includìng yeìlon'ish reducllon spols. 2-32 Pelleted algal nud I r'. 1r' rJJ 'ntair'r u .hr.op.1 t'.1 uu lrrrnpoiì' rn.l brrr rtr lcì cr.r .rlr.rì r'..J . Jlorì1.! -1J f LnsroPlrvt(s ùlrri gJ\llùf'ì'Ll\ olrve (5Y Vsrcl) MO B 1: . tr'' ui, tut R ,la_,,t s A pale oÌj\.e (5Y V6iCl2) MC) A ìightgrar(l0YR\r7,tl) OFw A l.l< 0._5 \-.ll\ nrd ml-.r n, ,\.,ror,t)r(. .rn.t t;, ;-.,.15\ r: r ., g3r ron^o( q,95 i1.95 Silty sand. gray (sY V5.C I ) 0 5) l 1.5 Sllty sand. light gra) {5Y V7iC2) _0.62 2.55 Palustrine nud irulirdng rcduction lrlhrbrotrf (-.5YR llots. \i6ic.1) _t ,i I ti Pr rsrint nrr.l including rcducrion lìghlbfown(7.5YR.fo,.. \ " a.i) -t Ro ì ln L.rgL',r.r rrud containìng charoph)les. gfa-vish bro*n (2.5 Y 8/'.rolod..nd b \î 'c. i: a: -2.02 3.92 l-agoonal mrid conreining gastropods. light gray (5Y \r7lc l) ,,rrt oFw OF'W \,JO N40 N4() lvlO C C C B B c' 0 7q 0.70 Clayel .silr. 0.50 0.95 clltrllr fllr: 0.20 L20 Sand), silt. -L00 1.30 Lagoonal md. ìight grav (5\' V7[2) brrren grar (5Y \5,c1) !q].-l llght gray 15Y V7rC2) Ofw C gfîvish bror,n (2.5 t tntO : \j5rc2) Introduction The elongated, NE-S\í oriented, Marathon plain is located in East Attica, E. Greece (Fig.t). The broader area surrounding the Marathon plain consists of the "NE Attica" geotectonic unir, represenring a "relatively auto- chthonous" metamorphic sequence (Lozios 1993). The Quaternary is represenred by various rypes of alluvial deposits formed mainly b1' the Inois river, ivhich divides the plain into two parrs. Pleistocene and Flolocene talus cones and screes cover steep valley sides as well as fault zones. The marsh of Marathon is extended at the eàstern side of the plain and separated from the sea by a barrier beach with low sand dunes, morphologically resembling the typical coastal plains of Greece according to Kraft (Kraft et al. 1975,1977). Baeteman (1985) conducted a systemaric drill hole studv of the area and presented detailed informarion on the stratigraphic sequence of the plain. Pavlopoulos et al. (in press) determined the sequence of depositional envi- ronments and the climate and sea let'el chanees recorded in the area since about 6000 years BII using rnicron.rorpho- logical and micropaleontological methods in addition to radiocarbon dating of seyeral horizons, including peat lalr- ers. They recognised three sedimentary units, nan-ìed A, B and C respectively (Fig. 2), on the basis of the features of each sedimentary phase. Sedimentary unit A (before 55OO to 3500 BP) is generally composed of fossiliferous biotur- Paleoent,ironmental changes on the Coastal plain 541 Tab. 1 - Descriptìon of tbe samples studicd and their relation with sedimentary units and bio- facies. bated lagoonal mud with occasional peloidal charophytic mud, algal peats and macrophytic peats. Unir B (3500- 2500 BP) consists of mixed carbonare and siliciclastic palustrine mud and the uppermost sedimenrary unit C (2500 BP-Present) represents mosrly fluvial deposits. The Marathon coastal plain is famous for the an- cient battle of 490 BC, fought between the Athenians and the Persians. This area rÀras proclaimed a national park by the Greek government after Athens won rhe comperirion for the organization of the 2OO4 Olympic Games. FIow- ever, a ros/ing center has been under construction since early 2001. Given the great environmenral and archaeo- logical importance of the area, great inrerest developed for understanding the palaeoenvironmental conditions of this plain in the past. This paper presents a detailed micropaleontological study of the subsoil of Marathon coasral plain. Taking into account the benthic foraminiferal and ostracode assemblages (together with sedimentological data; Pavlopoulos et al. in press) the analysis arremprs ro determine the paleoenvironmental changes during the last 6.000 yrs on the coastal plain of Marathon, based on the study of the brackish marsh benthic microfauna. Materials and methods In order to obtain information about the Holocene stratigraphy under the Recent alluvial cover rwo bore- T6 foss-l T6 Pl B T6 P2 A î7-1 '7 Ostracodes Cyprldels ?òfosa (JoNEt 97% Cyprinotus salínus (Baaov) Cyprinotus sp. 0.50% I ^w^î^^.h) ò11;^1;.. 21, i.av. atv" 82% 6% 89.7% 74.5% 85% B./" 8.3% 17.4ó/ó 12% 2.9% 2.7% 12% AAa/. 3.6% 1.6% 3% 69.1% 1.8%298% 9% 5.7% 2.5% cpn!ptqps9g!.9;;; . i:ll"t) l Other Candoninae 12% 2.5ok 111.k 2o.B% 6% 10 .7'/. q 3%-, o 5x '16.9% 3.40/a 1% tzóÀ 0.5% 24.8./" 14.5% 13.8% 6.5% Limnocythere ínopínata (Berno) Limnocythere sp. 0.6% 1a/. 16% 0.5% 1.44/. a7% 3 B% 6.8% 44L 115% | glbba t2% 55.20/. 724/.(Reuoorc) llyocypri:trp] Daruinula stevensani (Bnnov & Roaenrsor) Herpgtggyp!$p- Benthic Foraminifers Ammonia beccaii (LTNNE) Haynesína germanica Haynesina depressula (WALKER & JACOB) Trichohyalus aguayoi (BERN.4UDEZ) Elphidium granosum 0.5% 0.5% 6% 0.9% 9A.4% 96.4% 3.670 1 00% 28.3% 2% 93.5%95% 3.6% 1.5% 4yó 35.2% 6.5% 1.À 36.5% :\+ / M.V. Triantaphyllou, K. Paalopoulos, T. Tsourou U M. D. Dermitzakis Tab. 2 - Relative percentage abundances of species in at least 3OO counts (ostracodes) / 2OO counts (benthic foraminifers), in the samples studied were treated with H,O, to remove the organic matter, and then washed through 63, L25,250, 500 pr.m sieves and dried in an oven at 50c C. Qualitative analysis was performed on all samples, and seventeen samples presented a foraminif- eral and ostracode abundance which was sufficient for the quantitative analysis. A subset of each sample (frac- tion of 1 2 5 p,m I b enthic f oraminif e rs, 2 5 Opcm/os rracodes ) was obtained using an Otto microsplitter untiÌ aliquots of at least 2OO benthic foidminifers and 300 osrracodes, respectively, remained. A scanning electron microscope analysis (SEM Jeol JSM 5600) was used to assist in the identifications. The taxonomy of benthic foraminifers in this paper is based upon Loeblich & Tappan (1988, 1994) and Bronnimann et al. (1992). Taxonomic references of the ostracodes include mainly Athersuch et al. (1989) and additionally Mazzrni et al (1999), Sun er al. (1999). The relative abundance of the species was treated in a Q-mode hierarchical analysis, performed to study similarities between samples, which is based on Euclid- ian metric distance and was carried out using Statgraph- ics Plus 4.0 statistical software. Fig. 3 - Distrìburronef p:rrern of benrhìc forrminifcr. \r, and o.lrr- codes (b) in borehole /. holes were driiled -with a portable drilling set- and 4 trenches were excavated (Fig. 1). The description of the sediments in the sequences and their stratigraphic cor- relation are presented in Table 1 and Fig.2 . Twenty-one samples of about 50 g each were col- lected from all the boreholes and trenches (Fig. 2). They Benthic foraminifers and ostracode distribution and mi- crofaunal biotopes The species diversity of benthic foraminifers is very low. Only six species were actually identified in seven- teen samples. Concerning the ostracode fauna, twelve taxa were identified and counted (Table 2). Ammonia beccarii generally follows Haynesina spp. frequency pattern (Figs. 3a, 4a,5a, 6a) except for sample T8-3 where it shows an opposite trend, towards Haynesina germanica (Fig. aa). Additionally, A. becca- rli shows a negative trend towards Trichobyalus aguay- ol in sample T6-P2A (Unit A, borehole 6) . Concerning the relative frequency patterns of ostracode species, a *"'s .r.C *."u,".a"J ]ilirli LL-L r'"è' _.3 T uI l^l L_.1 .9^ .d """d -."e.nt* Ò\ Bg Sdmples î *i l::i F] H tl I'l ! H ".PlJnils Sqmples (J "d os s' -uu .''l.o'";S' Lll lf lrt rrl ll' I i ' I 'r, ,ro . .r, i ri---: ò--,0 do o 5 Fig. 4 - Dirtributional patLern ol bcnrhic ior:minr[er. 1:; :nd o,rra- codes (b) in trench 4. negative trend emerges in all the units between Cypri- deis torosa and Cyprinotws salinus, Darwinula ste-,tensonì, Limnocythere sp., Cand,ona neglecta and llyocypns spp. (Figs. 3b, 4b, 5b, 6b). The frequency data indicate that several changes in the composition of the benthic mi- crofauna took place in time and space on the coastal plain of Marathon. These changes were confirmed when Q- mode cluster analysis was applied to the data set to define areas of similar environmental conditions. In the resulting dendrograms (Fig. Z) the clusters are regarded as biotopes and are interpreted as representing different ecological conditions. These biotopes together with the environmenral interpretation are: Cluster I. Tricbobyalws agwayoi, Candona neglec- ta, other Candoninae, Limnocythere inopinata, Danainwla s t ev en s o ni, I I iy o cy p r i s bra dy i, I ly o cyp ri s gìbóa as s embla ge. Shallow oligohaline - fresh water biofacies Paleoenr:irctnmental changes on the Coastal plain 543 (OFW). The first cluster considered (Fig.Z) is represented by samples T11-1, T10-4, T8-5, T8-6, T8-Z (belonging to Unit C); T6P1B (belonging to Unit B); and T7-5,T6P2A (belonging to Unit A). They are characterizedby the total absence of benthic foraminifers (except for the remarkable monospecific presence ol T. aguayoi, as a brakish water species (Bronnimann er aI. neZ\, ìn sample T6P2A). C. neglecta, D. stez,ensonì, L, inopinata, I. bradyi, I. gibba are indicators of shallow freshwater and oligohaline envìron- ments (Athersuch 1,979; Grafenstein et al. 2O0O; Mazzini et a\.1999; Athersuch 1979;Sokac 1978). This assemblage consisting of dominant freshwater ostracode species, associated with brackish water species (C. torosa, C. salinws) indicates the persistence of a re- stricted temporary communication vrith the sea (C1avé et al. 2001). It suggests a salinity of less than L5"/oo (Neale 1988) and fits well vrith high-middle marsh environmenrs (Scott et aL. 1979), indicating an approximate elevation of 20 cm above the mean paleo-sea level. Cluster II. Ammonia beccarii, Haynesina germanica, Haynesina depressula, Cyprideis torosa, Loxoconcha ellip- tica, Cyprinotus salinus assemblage. Shallow mesohaline-oligohaline biofacies (MO). The second cluster considered (Fig.Z) is represented by samples T8-1, T8-2, T7-1, T6FOSS1, T10-5 (belonging to Unit A) and T8-4, T8-3 andTt-9 (belonging to Unit B), which are characterized by the high percentages (ris- ing up to 100%) of benthic foraminifers A. beccarii or H. germanica and H. depressula. A. beccarii -an euryhaline species living in a wide range of different environments (Murray 1991; Alve 1995) - is characteristic of the part of the lagoon which is more affecred by marine warers. whereas Haynesina is found in the internal portions of the lagoon affected by anthropogenic events (Serandrei Barbero et aL.1997). Both species characterize the lower intertidal environments (Cundy et a1. 2000).The ostra- code fauna is marked by the dominance oî C. torosa, ris- ing up to 97o/o, L. elliptica and C. salinws, which are typical brackish species (Gliozzr &'Mazzint 1.998;Mazzrni et aI. 1999). This assemblage suggests a salinity of more than 15 %' (Neale 1988) and fits well with low marsh environ- ments (Scott 1977;Scort et aI.1979; Petrucci et al. 1983), indicating approximately the mean paleo-sea level. Cluster III. Cyprideis torosa, Cyprinotus salinus, Candona neglecta, Limnocythere sp., Dalwinula stezten- son I assemblage. Shallow mesohaline-oligohaline to oligohaline- fresh-water biofacies (MO-OF\Q. As shown in Fig. 7, sample TZ-8 (belonging to the upper part of Unit A), which is characterized by the absence of benthic fo- raminifers and the balanced presence of brackish shal- low-water and shallow freshwater ostracode species, sug- gests an interrnediate mesohaline-oligohaline to oligoha- line-fresh-water lagoonal environment. 544 M.V. Triantaphyllou, K. Pavlopoulos, T. Tsourou g. M. D. Dermitzakis -$ "ts od òoii \t\t .-.d * .r.-uu ""S ...s .,"-- *.o.. ;'S I I EHll I'itil Fis. 5 - Distributional pattern of benthic forarninifcrs (a) and ostre- codes (b) in borehole 6. Paleoenvironmental interpretation and site evolution The biofacies documenred appear in all trenches and boreholes tTable l. Fig. 2 t. and therefore they char- acterize all the three different units. The MO biofacies (A. beccarii, Haynesina spp., C. ro- rosa, L. elliptica, C. salinus assemblage) of Unit A (5500-3500 BP) is present in trenches 10, 4 (located in the southern parr of the Marathon plain) and in the lower parts of boreholes Z and 6, indicating a brackish water marsh. The documentatron of OF\l and MO-OFV biofacies in boreholes 7 and 6, at levels where macrophytic and algal peats and characean oog- ons intercale rvith palustrine mud, suggesrs a brackish water marsh rvith fresh water inflow, probably associated ro sever- al shallowine cycles detected in the inner parts of the plain. Unit B (3500-2500 BP) has similar characteristics, since the OF\{/ biofacies is present only in borehole 6. Pavlopoulos et al. (in press) suggested frequent exposure of the basin during this time interval, which is definitely confirmed at the northern side of the plain by the terrestrial environment corresponding to substratum 25OOBP (docu- mented in sample T1-1 (trench 1) which conrains only verv few -probably not aurocrhonous- ostracode valves). The biofacies distribution is totally different in Unit C (25OO-Present). OF\f is the only biofacies detected at the southern part of the plain (trenches 11, 10, a) indi- cating the dominance of fresh warer ro oligohaline marsh environments. As Pavlopoulos et al. (in press) sugqesred, the change from palustrine to alluvial environment hap- pened repeatedly, implying a very shallow and frequently exposed plain without any connection to the sea. Fig. 6 - Distributional pattern of bcnthic foraminifers (a) and ostra- codes (b) ìn trench 10. Hence, towards the landward part of the Marathon coastal plain a general trend was documented along the transect A-B (Fig.8). As shown in Fig.8 during 55OO- 2500BP time interval, the southern part of the plain is con- sidered to represent a low marsh environment, whereas the rest of the area was a high-middle marsh. On the contrary the paleoenvironmental conditions changed drastically dur- ing the last 2500 yrs, as the high-middle marsh conditions were restricted to the sourhern part of the plain, while the northern part towards the landward area was probably ex- posed frequently. This is probably the result of a small ap- parent tectonic uplift the area underwent during the 55OO- 1300BP time interval, albeit ar slower rates (0.4-O.5mm/ Q-rlode hierarchjcal analvsis ieading to the distincrìon of three nrain clusters corresponding to different biofacies. :-- o[oonoIne loIl-8 oligoholine - Íiesh woter -biofocies IMO-OFW) T7-r l8-3 t8-4 Tó-FOS5] Tj-g mesoholine - oligoholine biofociés I8-2 (tvlo) T8 l Tl 0-5 -l-tl A I t- W oligoholine' fresh wolef bÌofociès(oF\tl Tó.P] B t6-P24, l8-7 r8-ó 17-5 r8-5 Il 0-4 nl-l F rg,. 7 Unit C 2500BP-presenl Unit B 3500-2500 BP Unit A beforè 5500-3500 BP yr; Pavlopoulos et al. in press) than the isostatic rate (0.6- A.7mm/yr, Lambeck 1996), which caused apparenr coasral stability from the Classical times onward (Kraît 1972). Conclusions The sedimentary sequences of the Middle-Late Holocene of the Marathon plain are represented gener- ally by lagoonal formations related to a slowing of the sea-level rise. The micropaleontological analysis at the Holocene coastal plain of Marathon revealed the absence of agglutinated foraminifers and hence the absence of a sait marsh paleoenvironmenr (Scorr et al. 1979; Cundy et al. 2000). One prominenr featllre of the present study is the clarification of the ecological preference of the species Trichohyalus aguayoi (Bermudez, 1935), (P1. I, figs 1, 2), Paleoenoironmental changes on the Coastal plain 515 Fi-. I - Schem.rric inrernrcrrrion oI- b'" paleoenvironmental conditions of the study area, according to the biofacìes ìdentified in the sedimentary units A, B, C. (T: trench, B: borehole) which is generally regarded as a brackish species (Bronni- m.lnn cî rl. lgg)r. Scor. ^* ^l r roTo\ J^^,.- .-led iL underuv!uillLlll the name Dicorinopsis aguayoi in recenr coasral marshes of \il{ Greece. Our results clearly indicate that it dominates in oligohaline conditions (salinity of less than 15 "/"'). Three biofacies were recognized in sedimentary units (Pavlopoulos et'al. in press) of the Marathon plain during the last 55OOyrs. The alternation of MO, OFV and MO-OF\f biofacies in the framework of the sedimentary units indicates a seneral trend towards the landward area of the plain, suggesting a slowing of sea-level rìse prob- ably correlated with a relevant tectonic uplift. Akno'oletlgments. \fle thank Dr. M. Dimiza for her help in treat- ing the data st:rtistically and taking the SEM micrographs. The authors also would like to thank D. Besso, A. Bossio and M. Geetani nhose in- cisive and constructive comnrents greatly improved the nrrnuscrìpt. REFERENCES Alve E. (1995) - Benthic foraminiferal distribution and rcc- olonization of forncrlv :rnoxic environments in Dram- rnensflord, southern Norw:Lv. Mar. Micropal., 25 (2-3): I69-186, Arnsterdam. Athersuch I. 0979) - The ecology and distribution of the lit- toral ostracodes of C1'prus./. of Nat. Hist.,13:135-160, London. 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(1997) - Palaeoenvironmental significance of a benthic foraminif- eral fauna from an archaeological excavation in the La- goon of Venice, Italy, Palaeogeogr., Palaeoclim., Palae- oecol., 136 (l -4) : 41 -52, Amsterdam. Sokac A. (1978) - Pleistocene osrracode fauna of the Pannonian Basin in Croatia. Palaeontol. Jugosl.,2e: 1,-51,Zagreb. Sun 2., Feng X., Li D., Yang F., Qu Y & \X/ang H. (1999) - Ceno- zoic Ostracoda and palaeoenvironments of the northeast- ern Tarim Basin, western China. Palaeogeogr., Palaeoclim., Palaeoecol., 148 37 -50, Amsterdam. PLATE I Fig. 1 T)"ichohyalus aguayoi (Bermtdez). Umbilical vierv, sample T6P2A. Fig.2 hichohyalus aguayoi (Bermudez). Dorsal vier., sample T6P2A. Fig.3-Ammoniabeccarii (Linne). Umbilicalview,sampleT6IjOSSl. Fig.4-Haynesinadepressula(\falkertrJacob).Sideview,sanr- ple T6FOSS1. Frg 5 - Chara sp. Sample T1O-3. Fig. 6 - Daruinula stevensoni (Brady & Robertson), san.rple T /-5, left valve, exrernal vien. Fìg 7 Loxoconcha elliptìca Brady, sample T6 Foss1, right valve, external view. Frg. 8 - Candona neglecta Sars, sample T6 p1B, right valve, external vieu'. Ftg.9 - Cyprinotus salinus (Brady), sample T Z-5, right valve, external view. Fig. 1O - Ilyocypris brarlyi Sars, sample T6 plg, 1.ft valve, ex- ternal view. Fig. 11 - Ilyocypris gibba (Ramdohr), sample T6 P1B, left valve, external view. Frg. 12 Cypr:ideis torosa (Jones), sample T6 Foss1, female, left valye, externàl vierr. Pttleoert'-ìrotnnentaL cbanges ctn the CoastaL plain 517