01 tesovic-mezga-glumac.indd 3 � 1. INTRODUCTION Di no saur foot prin ts we re dis co ve red re cen tly in Up per Tit ho- nian stra ta expo sed in an ac ti ve quar ry near Kir me njak vil la ge (about 2 km sou th of the Sv. Lov reč–Po reč road) in wes te rn Is tria, Croa tia (MEZGA et al., 2003; MEZGA et al., 2007) (Fig. 1). The Is trian pe nin su la is in the nor thwes te rn pa rt of the Ad ria ti c-Di na ri dic Car bo na te Plat fo rm, (ADCP; al so re fe- red to as Ad ria tic Car bo na te Plat fo rm, see dis cus sion in VLAHOVIĆ et al., 2005). The se di men ta ry suc ces sion main ly con sis ts of shal low wa ter car bo na tes wi th a stra tig rap hic ran ge from the la te Mid dle Ju ras sic to the Eo ce ne (VELIĆ et al., 2003), and to a les ser exte nt of Eo ce ne clas tic roc ks and Qua ter na ry ter ra ros sa and loe ss de po si ts. The Kir me njak lo ca- li ty rep re sen ts the ol de st evi den ce of a di no saur pre sen ce on the ADCP to da te, wi th a to tal of 971 do cu men ted foot prin ts. It al so rep re sen ts the lar ge st si te wi th di no saur trac ks dis co ve- red on the ADCP so far (MEZGA et al., 2007), wi th 23 trac k- ways, and ot her foot prin ts oc cur ri ng in di vi dual ly or in grou ps. Based on their ove ra ll mor pho lo gy, the foot prin ts are at tri bu- ted to sau ro pod di no sau rs. The ob jec ti ve of this stu dy was to use stab le iso to pes of oxygen and car bon in co njun ction wi th pet rog rap hic ob ser- va tio ns of car bo na te roc ks, to un ra vel de tai ls about the mar gi- nal ma ri ne or coas tal en vi ron men ts in whi ch lar ge quad ru pe- Blanka Cvetko Tešović1, Aleksandar Mezga1 and Bosiljka Glumac2 AB STRA CT The Kirmenjak locality of western Istria, Croatia, represents the oldest evidence of a dinosaur presence on the Adri- atic-Dinaridic Carbonate Platform (ADCP). In a quarry at this locality, almost a thousand sauropod footprints are recognized in one distinctive trackbearing horizon within the Upper Tithonian limestones. The stable isotopes of oxygen and carbon, in conjunction with microfacies analysis of carbonate rocks exposed in this quarry, unravel de- tails about the marginal marine or coastal environments in which sauropods left their footprints. Rocks from the trackbearing horizon, and laterally adjacent area, represent intertidal fenestral mudstones that form the top of a shal- lowing-upward succession, capped with a thin peloidal packstone/grainstone layer and overlain by subtidal mud- stone. The formation and preservation of footprints was favoured by short-duration exposure of muddy sediment and its rapid burial beneath more mud. The isotopic composition of the sample from the trackbearing horizon is not sub- stantially different from those of an adjacent area without footprints and from the overlying mudstone. Stable isotope analysis supports petrographic observations that the conditions on the carbonate tidal fl at during formation of rocks with dinosaur footprints were not unique. Documented variations in stable isotope compositions refl ect minor differ- ences in the depositional and diagenetic history of the Kirmenjak quarry succession. Keywords: Stable isotopes, Palaeoenvironments, Sauropods, Upper Tithonian Limestones, Istria, Croatia. 1 Department of Geology, Faculty of Science, University of Zagreb, Horvatovac 102a, HR-10 000 Zagreb, Croatia; (bcvetko@geol.pmf.hr, amezga@geol.pmf.hr) 2 Department of Geology, Smith College, Northampton, Massachusetts 01063, USA; (bglumac@email.smith.edu) Stable isotope analysis of Upper Tithonian limestones with dinosaur footprints from Kirmenjak quarry (Istria, Croatia) Geologia Croatica 61/1 3–9 8 Figs. 0 Tabs. Zagreb 2008 Geologia CroaticaGeologia Croatica � 01 tesovic-mezga-glumac.indd 301 tesovic-mezga-glumac.indd 3 24.6.2008 11:04:4124.6.2008 11:04:41 Geologia Croatica Geologia Croatica 61/1 4 dal sau ro pod di no sau rs le ft their foot prin ts du ri ng the La te Tit ho nian (MEZGA et al., 2007). The stu dy was car ried out on a por tion of the Kir me njak quar ry de po si ts (Fig. 2) that be lo ng to the in for mal Kir me njak unit (VELIĆ & TIŠLJAR, 1988). The fo cus was on a ho ri zon wi th abun da nt di no saur foot prin ts lo ca ted ap proxi ma te ly in the mid dle of the suc ces- sion (Fi gs. 2, 3). 2. METHODS Fiel dwo rk in vol ved mea su ri ng, des cri bi ng and sam pli ng of a 14.5 metre thi ck suc ces sion of Up per Tit ho nian car bo na te roc ks (Fig. 2) in the Kir me njak quar ry. Pet rog rap hic ana lysis was used to fur ther des cri be ro ck types pre se nt and to iden ti fy sam ples for stab le iso to pe ana lysis, whi ch we re col lec ted by the dril li ng of a sma ll amou nt of car bo na te powder wi th a mic rod ri ll moun ted on a bi no cu lar mic ros co pe. All sam ples for stab le iso to pe ana lyses we re roas ted at 380°C for one hour to re mo ve vo la ti le or ga nic mat ter, reac ted wi th 100% H3PO4 at 70°C for 5 mi nu tes and ana lyzed usi ng an on-li ne, au to ma- ted car bo na te pre pa ra tion system (Kie ll III) lin ked to a Finni- gan-MAT DeltaXL+ ra tio ma ss spec tro me ter at the Uni ver si ty of Mas sac hu set ts, Amherst, USA. Stan da rd iso ba ric and phos- pho ric acid frac tio na tion cor rec tio ns we re ap plied to all re sul ts and ana lyti cal pre ci sion was mo ni to red throu gh dai ly ana lysis of a va rie ty of car bo na te stan dar ds. 3. GEOLOGICAL SETTING The stra tig rap hy and the tec to nic and geo lo gi cal his to ry of Is tria are sum ma rized in the expla na to ry no tes to the Ba sic Geo lo gi cal Map of Croa tia, Sheet Ro vinj (POLŠAK & ŠIKIĆ, 1973). De tai led lit ho fa cies and bio fa cies in ves ti ga tio ns of shal- low wa ter car bo na tes in Is tria we re car ried out in the 1970s and the li st of im por ta nt re fe ren ces can be fou nd in VELIĆ et al. (2003). The Is trian stra tal suc ces sion can be di vi ded in to fi ve se di- men ta ry uni ts or lar ge-sca le sequen ces boun ded by im por ta nt dis con ti nui ties rep re sen ti ng emer sion sur fa ces of va ryi ng du ra- tion (VELIĆ et al., 2003). The se lar ge-sca le sequen ces or me ga sequen ces are: (1) Bat ho nian–lower mo st Kimmerid gian, (2) Up per Tit ho nian–Lower or Up per Ap tian, (3) Up per Al bian–Up per San to nian, (4) Eo ce ne, and (5) Qua ter na ry. The in ves ti ga ted stra ta from the Kir me njak quar ry be lo ng to the se co nd tran sgres si ve-reg res si ve me ga sequen ce (Up per Tit ho nian–Lower or Up per Ap tian), de po si tion of whi ch star- ted in the La te Tit ho nian wi th shal lowi ng-u pwa rd li mes to ne cycles for med in sub ti dal, in ter ti dal and sup ra ti dal en vi ron- men ts (VELIĆ et al., 2003; VLAHOVIĆ et al., 2003). This li mes to ne is known as the ar chi tec tu ra l-buil di ng sto ne »Piet ra d’Is tria« or »Kir me njak«. The de po si ts of the Kir me njak unit exa mi ned in this stu dy (Fig. 2) rep re se nt al ternation of metre sca le shal lowi ng-u pwa rd cycles com po sed of bla ck peb ble brec cias or stylo li ti zed mud sto ne at the ba se, over lain by fe nes tral mud sto ne, and com mon ly cap ped by pe loi dal pac ksto ne and/or grain sto ne (VELIĆ & TIŠLJAR, 1988; TIŠLJAR et al., 1995; MEZGA et al., 2007). The pre sen ce of bla ck peb ble brec cias sug ges ts that stra ta expo sed at the Kir me njak lo ca li ty li ke ly be lo ng to the lower pa rt of the Kir me njak unit, i.e. to the lower mo st pa rt of the se co nd Is trian me ga sequen ce (VELIĆ & TIŠLJAR, 1988). 4. ICHNOLOGY The in ves ti ga ted si te is ve ry ri ch in di no saur foot prin ts: al mo st a thou sa nd in di vi dual prin ts ha ve been ob ser ved on the trac kbea ri ng layer expo sed in the Kir me njak quar ry (MEZGA et al., 2007; Fig. 3). Mo st of the foot prin ts ha ve an oval or hor ses hoe sha pe wit hout clear ly vi sib le di git im pres sio ns (Fig. 4), and are re la ti ve ly shal low (1–2 cm). The ova l-sha ped prin ts rep re se nt pes prin ts and the hor ses hoe-sha ped prin ts are ma nus prin ts (Fig. 4). The foot prin ts are of va rious di men sio ns: the ma nus prin ts ha ve a len gth ran gi ng from 5.5–26.5 cm, and the pes prin ts from 23–52 cm. The calculated hip heig ht ran ges from 153–306 cm. The re are 23 trac kways do cu men ted at this si te and they frequen tly over lap. The trac kways show cha rac- te ris ti cs of a nar row-gau ge type (Fig. 5). The pa ce and stri de lengths in di ca te slow wal ki ng in di vi dua ls. The main di rec tion of di no saur mo ve me nt is towar ds the NE and be cau se the re are ma ny pa ral lel trac kways it may be con clu ded that so me of the in di vi dua ls we re mo vi ng to get her in a he rd (in di ca tion of grega rious be ha vior). Althou gh the sta te of pre ser va tion is far from ideal, the prin ts be lo ng to sau ro pod di no sau rs ba sed on their ove ra ll mor pho lo gy (MEZ GA et al., 2007). The foot prin ts are si mi lar to Pa rab ron to po dus ic hno ge nus and the ic hno coe no sis is as sig- ned to the Bron to po dus ic hno fa cies, whi ch is cha rac te ri zed by sau ro pod foot prin ts in car bo na te plat fo rm en vi ron men ts. 5. LITHOLOGY AND MICROFOSSIL ASSEMBLAGE Seve ral shal lowi ng-u pwa rd cycles are dis tin guis hed in the in ves ti ga ted suc ces sion, ran gi ng in thic kne ss from 0.3 to 2 m Fi gu re 1: Geog rap hic and geo lo gic set ti ng of the Kir me njak lo ca li ty in Is tria, Croa tia (mo di fi ed af ter VELIĆ et al., 1995). 01 tesovic-mezga-glumac.indd 401 tesovic-mezga-glumac.indd 4 24.6.2008 11:04:4224.6.2008 11:04:42 Geologia Croatica 5 Blanka Cvetko Tešović et al.: Stable isotope analysis of Upper Tithonian limestones with dinosaur footprints from Kirmenjak quarry (Fig. 2). The shal lowi ng-u pwa rd cycles be gin wi th bla ck peb ble brec cia (in two cycles) or stylo li ti zed mud sto nes, fol lowed by fe nes tral mud sto ne, and com mon ly end wi th pe loi- dal pac ksto ne/grainstones and grain sto nes (Fig. 6). The mudsto nes are mas si ve, hig hly stylo li ti zed (Fig. 6), oc ca sio- nal ly bio tur ba ted, ra re ly la mi na ted, lig ht yel lowi sh gray in co lour, and in pla ces in ter bed ded wi th len ses and laye rs of pe loi dal pac ksto ne to grain sto ne. Ra re fos si ls in clu de os tra- co ds, green al gae, gas tro po ds, sma ll fo ra mi ni fe ra and crus ta- cean pel le ts Fav rei na. The se de po si ts are in ter pre ted as rep re- se nting a sub ti dal en vi ron me nt, pro bab ly a res tric ted la goon. Bla ck peb bles (Fig. 6) in cor po ra ted in the ba se of so me mud sto ne ho ri zo ns sug ge st rewor ki ng of mar sh de po si ts du ri ng sea-le vel ri se. Mud sto nes com mon ly gra de upwa rd in to fe nes tral mud sto ne (Fi gs. 2 & 6). The fe nes tral mud sto nes (Fig. 6) are in pla ces al so in ter- bed ded wi th len ses and laye rs of pe loi dal pac ksto ne to grain- sto ne wi th mm-sca le mud dy in trac las ts. Com mon mm-sca le Fi gu re 2: Sche ma tic lit ho lo gic co lu mn of the mea su red Kir me njak quar ry suc ces sion wi th mea su red d13C and d18O va lues. On ly exam ples of pro mi ne nt shal lowi ng-u pwa rd suc ces sion to ps are in di ca ted on the stra tig rap hic co lu mn. 01 tesovic-mezga-glumac.indd 501 tesovic-mezga-glumac.indd 5 24.6.2008 11:04:4224.6.2008 11:04:42 Geologia Croatica Geologia Croatica 61/1 6 fe nes tral voi ds are fi l led wi th spa ri te and are main ly ir re gu lar in sha pe, whe reas la mi nar fe nes trae or sheet crac ks are not as abun da nt. Sub ver ti cal to ir re gu lar mm- to cm-sca le de sic ca- tion and dis so lu tio n-en lar ged voi ds wi th geo pe tal in fi l ls of va do se si lt and coar se-crystal li ne clear equa nt cal ci te ce me nt are pre se nt in so me of the fe nes tral mud sto nes (Fig. 6). The fe nes tral mud sto nes ra re ly fo rm in si tu brec cia ted shal lowi ng- u pwa rd cycle to ps wi th rewor ked mud dy in trac las ts. The fe nes- tral mud sto nes are in ter pre ted as having for med in res tric ted shal low sub ti dal to in ter ti dal en vi ron men ts and they com mon ly gra de upwa rd in to pe loi dal grain sto ne (Fig. 6). The pe loi dal pac ksto ne/grainstones to grain sto nes (Fig. 6) are cha rac te ri zed by abun da nt ir re gu lar fe nes trae and com mon in ter va ls wi th mm-sca le in trac las ts that fo rm dar ker grayi sh to browni sh co loured shal lowi ng-u pwa rd cycle to ps wi th in si tu brec cia tion. The se cycle to ps are al so cha rac te ri- zed by dar ke ned clas ts (bla ck peb bles), mm- to cm-sca le de sic- ca tion and dis so lu tio n-en lar ged voi ds wi th geo pe tal in fi l ls (Fig. 6), thin cal cre te crus ts, and cm-sca le clay-ri ch ca ps. The pe loi dal pac ksto ne/grainstones to grain sto nes from the up per- mo st par ts of shal lowi ng-u pwa rd cycles are in ter pre ted as de po si ts of in ter ti dal to sup ra ti dal en vi ron men ts for med by hi gh ener gy sto rm wa ves and ti des. Mo di fi ca tio ns un der su bae- rial expo su re con di tio ns pro du ced cha rac te ris tic cycle to ps. Sam ples from the trac kbea ri ng ho ri zon and ad ja ce nt area wit hout foot prin ts are lit ho lo gi cal ly ve ry si mi lar. They con si st of mud sto nes wi th sma ll fe nes trae, fai nt la mi na tion and rat her lar ge sub ver ti cal to ir re gu lar de sic ca tion crac ks and voi ds. The up per mo st pa rt of bo th con sis ts of a thin layer of pe loi dal pac ksto ne/grainstone (Fig. 6). Laye rs di rec tly over lyi ng the foot pri nt ho ri zon, on the ot her ha nd, are qui te dif fe re nt – they are mas si ve stylo li tic mud sto nes. The pre sen ce of fe nes trae and de sic ca tion fea tu res sug ges ts that the roc ks wi th di no saur foot prin ts we re for med in an in ter ti dal en vi ron me nt. The la ck of fe nes trae and ot her in di ca to rs of su bae rial expo su re in the mud sto nes abo ve the foot prin ts sug ge st for ma tion in a sub ti- dal en vi ron me nt. Thus, the foot prin ts for med on top of a shal- lowi ng-u pwa rd suc ces sion (Fig. 6), whi ch is over lain by dee per, sub ti dal de po si ts. Palaeoen vi ron men tal con di tio ns du ri ng de po si tion of the Kir me njak quar ry suc ces sion were not op ti mal for hi gh bio tic pro duc ti vi ty. Mic ro fos sil re mai ns in clu de on ly a few taxa of cal ca reous al gae, whi le ben thic fo ra mi ni fe ra are ve ry ra re. The mic ro fos sil as sem bla ge (Fig. 7) con sis ts of Cam pbel liel la Fi gu re 3: Pa no ra mic view of the trac kbea ri ng ho ri zon in the Kir me njak quar ry. Fi gu re 4: An ova l-sha ped pes pri nt (lower pa rt of the pho tog ra ph) and a hor ses hoe-sha ped ma nus pri nt (up per pa rt of the pho tog ra ph) of the sau ro pod dinosaur from the Kir me njak quar ry. Fi gu re 5: A nar row-gau ge trac kway of a sau ro pod di no saur from the Kir me njak quar ry. 01 tesovic-mezga-glumac.indd 601 tesovic-mezga-glumac.indd 6 24.6.2008 11:04:4324.6.2008 11:04:43 Geologia Croatica 7 Blanka Cvetko Tešović et al.: Stable isotope analysis of Upper Tithonian limestones with dinosaur footprints from Kirmenjak quarry stria ta (CAROZZI) (Fig. 7A), Fav rei na sp. (Fig. 7B) and Sal pin go po rel la an nu la ta CAROZZI (Fig. 7C-D), as we ll as other uniden ti fi ed fo ra mi ni fe ra, gas tro po ds, os tra co ds and ec hi- noi ds. The iden ti fi ed mic ro fos sil as sem bla ge, typi cal of the Kir me njak unit, con fi r ms a La te Tit ho nian age. 6. STABLE ISOTOPE RESULTS Stab le iso to pe va lues of the 32 sam ples ana lyzed from the stu died suc ces sion (Fi gs. 2 & 8) are lower than the es tima ted va lues of Up per Ju ras sic unal te red ma ri ne cal ci te (δ18O = -2 to -1‰; δ13C = +3 ‰; LOH MA NN & WAL KER, 1989). All sam ples ha ve po si ti ve δ13C va lues exce pt for the three who le- ro ck sam ples of pe loi dal pac ksto ne-grain sto ne from be low a pro mi ne nt su bae rial expo su re ho ri zon wi th bla ck peb bles in the mid dle of the sec tion (Fig. 2). The re st of the da ta poin ts show a ge ne ral co va rian ce be tween δ13C and δ18O va lues, and an over lap be tween com po si tio nal fi el ds rep re sen ti ng dif fe re nt ro ck types (Fig. 8). Mud sto nes, howe ver, te nd to clus ter towar ds mo re ne ga ti ve δ13C and δ18O va lues, and fe nes tral mud sto nes and pe loi dal pac ksto ne-grain sto nes plot towar ds mo re po si ti ve va lues (Fig. 8). Excep tio ns are one fe nes tral mud sto ne sam ple (δ13C = 0.28 ‰) and one mud sto ne sample (δ13C = 1.48 ‰) from the ba se of a shal lowi ng-u pwa rd suc ces- sion. The sam ple wi th di no saur foot prin ts is not sub stan tial ly dif fe re nt from tho se of the ad ja ce nt area wit hout foot prin ts and from the over lyi ng mud sto ne (Fig. 8). 7. DISCUSSION Pet rog rap hic ob ser va tio ns do not explain why the re are no foot prin ts alo ng the sa me in ter ti dal ho ri zon in dif fe re nt pla ces in the quar ry. It is pos sib le that the foot pri nt dis tri bu tion refl ec ts mi nor dif fe ren ces in wa ter dep th, whi ch are not refl ec- ted by lit ho lo gi cal chan ges. It is al so pos sib le that foot prin ts we re not ob ser ved in ot her si mi lar ro ck types in the quar ry be cau se mo st of the ot her to ps of the shal lowi ng-u pwa rd suc ces sio ns are now cap ped by pro mi ne nt stylo li tes and thus the foot prin ts, if they we re the re, may ha ve been ob li te ra ted by pres su re dis so lu tion alo ng stylo li tes. Bed-pa ral lel stylo li tes are extre me ly abun da nt in the Kir me njak de po si ts, and lo cal ly the se stra ta are com mon ly re fer red to as the stylo li tic li mes to nes. The ob ser ved abun- dan ce and mor pho lo gy of stylo li tes all poi nt towar ds a po ten- tail ly sub stan tial mag ni tu de of pres su re dis so lu tion and thic- kne ss re duc tion of the Kir me njak stra ta du ri ng bu rial dia ge ne sis. Am pli tu de of stylo li tes sug ges ts that the pri ma ry thic kne ss of the se Tit ho nian li mes to nes may ha ve been re du- ced by about 20–23% (TIŠLJAR, 1978). Fur ther mo re, it may be sig ni fi ca nt that the shal lowi ng- u pwa rd suc ces sion wi th di no saur foot prin ts ter mi na ted in fe nes tral mud sto ne (wi th on ly a ve ry thin cap of pe loi dal pac ksto ne/grainstone; Fig. 6) rat her than in thic ker shal low in ter ti dal to sup ra ti dal grain sto ne de po si ts wi th sub stan tial evi den ce for mo di fi ca tion du ri ng su bae rial expo su re. Foot- prin ts li ke ly ha ve a bet ter po ten tial of bei ng pro du ced and pre ser ved in mud dy (rat her than grai ny) se di me nt that was dried out du ri ng a rat her brief pe riod of expo su re in an in ter ti- Fi gu re 6: De tai ls of shal lowi ng upwa rd cycles from the cen tral pa rt of the mea su red Kir me njak suc ces sion (see al so Fig. 2). The cycles be gin wi th bla ck peb ble brec cias (A) or stylo li ti zed mud sto ne (A’), over lain by fe nes tral mud sto ne (B) and pe loi da l-in trac las ti c-fe nes tral pac ksto ne wi th geo pe tal in fi ll (C), and cap ped wi th thin pe loi da l-in trac las tic grain sto ne (D) wi th di no saur foot prin ts (E). 01 tesovic-mezga-glumac.indd 701 tesovic-mezga-glumac.indd 7 24.6.2008 11:04:4624.6.2008 11:04:46 Geologia Croatica Geologia Croatica 61/1 8 dal en vi ron me nt and was then ra pid ly co ve red by sub ti dal mud. The ab sen ce of sub stan tial pres su re dis so lu tion (stylo li- tes) alo ng the bed di ng pla ne wi th foot prin ts, unear thed by quar ry ope ra tio ns, fur ther ai ded foot pri nt pre ser va tion. Stab le iso to pe re sul ts sup po rt pet rog rap hic ob ser va tio ns that the ho ri zon wi th di no saur foot prin ts does not rep re se nt a unique ro ck type. Com pa ri son wi th unal te red Ju ras sic ma ri ne ce men ts and the co varian ce be tween δ13C and δ18O va lues (Fig. 8), sug ge st po st-de po si tio nal or dia ge ne tic mo di fi ca tio ns in the pre sen ce of me teo ric wa te rs. This is al so sup por ted by the pre sen ce of dis so lu tion en lar ged voi ds and their oc clu sion by va do se si lt and me teo ric cal ci te ce me nt (Fig. 6). Ne ga ti ve δ13C va lues re cor ded in the pe loi dal pac ksto ne-grain sto ne (Fi gs. 2 & 8) as so cia ted wi th the expo sed sur fa ce wi th bla ck peb bles, refl e ct dia ge ne sis un der su bae rial con di tio ns in the pre sen ce of ter res trial ly de ri ved de cayi ng orga nic mat ter. Va ria tio ns in δ13C and δ18O va lues in ot her ana lyzed sam ples (Fig. 8) are li ke ly a fun ction of mi nor va ria tio ns in con di tio ns du ri ng de po- si tion (tem pe ra tu re, sa li ni ty, or ga nic pro duc ti vi ty), and the exte nt of dia ge ne tic mo di fi ca tio ns. The ob ser ved over lap of com po si tio nal fi el ds sug ges ts that the ove ra ll con di tio ns du ri ng de po si tion and dia ge ne sis of va rious ro ck types did not va ry great ly in deed. The clus te ri ng of fe nes tral mud sto nes (a nd the re st of the pe loi dal pac ksto ne to grain sto ne sam ples) towar ds slig htly mo re po si ti ve va lues, may refl e ct their lit hi fi ca tion from wa te rs that expe rien ced en han ced exchan ge wi th the atmos phe re (in clu di ng eva po ra tion) du ri ng their re si den ce on the car bo na te ti dal flat. On the ot her ha nd, clus te ri ng of mud sto ne towar ds slig htly mo re ne ga ti ve va lues may in di ca te lit hi fi ca tion in the pre sen ce of a so mewhat grea ter amou nt of or ga nic mat ter in the se res tric ted sub ti dal/lagoonal de po si ts. The be gin ni ng of de po si tion of the Kir me njak unit is mar ked by an os cil la to ry tran sgres sion over the emer ged re lief (TIŠLJAR et al., 1995; VELIĆ et al., 2003). De po si ts in the lower pa rt of the Kir me njak unit in di ca te the pre sen ce of coas- tal mar sh en vi ron men ts, whi ch rep re se nt the sour ce for bla ck peb ble brec cias (VLAHOVIĆ, 1999). Wi th con ti nui ng tran s- gres sion, the se mar shes we re gra dual ly rep la ced wi th shal low, pro tec ted la goon en vi ron men ts sur roun ded by wi de ti dal fl a ts whe re di no sau rs le ft their foot prin ts. 8. CONCLUSION The Kir me njak quar ry in wes te rn Is tria, Croa tia, is cur ren tly the lar ge st di no saur foot pri nt si te on the ADCP wi th al mo st a thou sa nd in di vi dual foot prin ts pre ser ved in Up per Tit ho nian li mes to nes. Di no saur foot prin ts we re pro du ced on the top of a shal lowi ng-u pwa rd suc ces sion in in ter ti dal fe nes tral mud sto- nes, cap ped wi th a thin pe loi dal pac ksto ne/grainstone layer, and over lain by sub ti dal mud sto ne. Foot pri nt for ma tion and pre ser va tion was fa voured by sho rt-las ti ng expo su re of mud dy se di me nt and its ra pid bu rial be nea th mo re mud. The ab sen ce of sub stan tial pres su re dis so lu tion (stylo li tes) alo ng the bed di ng pla ne wi th foot prin ts, unear thed by quar ry ope ra tio ns, fur ther ai ded foot pri nt pre ser va tion. The re sul ts of pet rog rap- hic and stab le iso to pe ana lysis did not pro vi de any di re ct evi den ce that the con di tio ns on the car bo na te ti dal fl at du ri ng for ma tion of the de po si ts wi th di no saur foot prin ts we re unique. Do cu men ted va ria tio ns in stab le iso to pe com po si- tio ns, on the ot her ha nd, refl e ct mi nor dif fe ren ces in the de po- si tio nal and dia ge ne tic his to ry of stra ta from this stra tig rap hic suc ces sion. AC KNOWLED GMEN TS This re sear ch was pa rt of the Joi nt Re sear ch Pro je ct no. 7KRPJ065729 »Palaeos tu dies and re con struc tio ns of di no saur po pu la tio ns and their en vi ron men ts in Is tria and ad ja ce nt is lan ds (Croa tia) du ri ng the La te Ju ras sic and Cre ta ceous Fi gu re 8: d13C vs. d18O va lues of the ana lyzed sam ples. Fi gu re 7: Mic ro fos sil as sem bla ge of the Kir me njak unit from the Kir me njak quar ry. A, lon gi tu di nal and tran sver se sec tio ns of Cam pbel liel- la stria ta (CA ROZ ZI); B, fe nes tral mud sto ne wi th com mon Fav rei na sp.; C, al gal mud sto ne wi th tran sver se sec tio ns of Sal pin go po rel la an nu la ta CAROZZI; and D, al gal mud sto ne wi th va rious sec tio ns of S. an nu la ta CAROZZI. 01 tesovic-mezga-glumac.indd 801 tesovic-mezga-glumac.indd 8 24.6.2008 11:04:4724.6.2008 11:04:47 Geologia Croatica 9 Blanka Cvetko Tešović et al.: Stable isotope analysis of Upper Tithonian limestones with dinosaur footprints from Kirmenjak quarry pe rio ds (170–90 Ma)« spon so red by the Swi ss Na tio nal Scien ce Foun da tion. The wo rk was al so sup por ted by gran ts from the Croa tian Mi nis try of Scien ce, Edu ca tion and Spo rt (pro je ct nos. 119–1191152–1169 and 19–1191152–1171). Fi nan cial sup po rt was al so pro vi ded by the STRIDE Fel lowship Prog ram at Smi th Col le ge and by re sear ch gran ts from the Mel lon Foun da tion and from the Wo me n’s In ter na- tio nal Scien ce Col la bo ra tion (WISC) Prog ram of the Ame ri- can As so cia tion for the Ad van ce me nt of Scien ce, fun ded by the U.S. Na tio nal Scien ce Foun da tion, ad mi nis te red throu gh Smi th Col le ge. Our spe cial than ks go to D. PU TI NJA, M. HVA LA and ot her em ployees of »Ka men Pa zin d.d.«. We are than kful to C. TEWKSBU RY (STRIDE Fel lowship Prog ram at Smi th Col le ge) for her as sis tan ce wi th sam ple pro ces si ng and ini tial da ta in teg ra tion, to T. CAL DA NA RO (Smi th Col le ge) for his he lp wi th thin sec tion pre pa ra tion, and to Dr. S. BUR NS (Uni ver si ty of Mas sac hu set ts, Am her st, USA) for stab le iso to pe ana lyses. 9. REFERENCES LOHMANN, K.C & WALKER, J.C.G. 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