PROGRAM, ABSTRACTS and FIELD GUIDE

5th FIELD WORKSHOP IGCP 458 PROJECT Triassic-Jurassic Boundary Events 5–10 September 2005 TATA (Hungary) – PUCH bei HALLEIN (Austria)

PÁLFY, J. and OZSVÁRT, P. (eds.) 2005. Program, Abstracts and Field Guide. 5th Field Workshop of IGCP 458 Project (Tata and Hallein, September 2005). Editors: J. PÁLFY and P. OZSVÁRT, Research Group for Paleontology, Hungarian Academy of Sciences– Hungarian Natural History Museum, Budapest, Hungary, [email protected]; [email protected]

Contributors of the field guide: F. BÖHM, IFM-GEOMAR, Kiel, Germany, [email protected] G. CSÁSZÁR, Hungarian Geological Institute, Budapest, Hungary, [email protected] S. DELECAT, GZG Universität Göttingen, Geobiologie, Göttingen, Germany, [email protected] A. DULAI, Hungarian Natural History Museum, Budapest, Hungary, [email protected] J. HAAS, Geological Research Group, Hungarian Academy of Sciences–Eötvös University, Budapest, Hungary, [email protected] L. KRYSTYN, Paläontologisches Institut der Universität, Vienna, Austria, [email protected] W. KÜRSCHNER, Section Palaeo-Ecology, Laboratory of Palaeobotany and Palynology, Utrecht University, The Netherlands, [email protected] A. ORAVECZ-SCHEFFER, Hűvösvölgyi út 74, Budapest, Hungary J. PÁLFY, Research Group for Paleontology, Hungarian Academy of Sciences–Hungarian Natural History Museum, Budapest, [email protected] O. PIROS, Hungarian Geological Institute, Budapest, Hungary, [email protected] I. SZENTE, Department of Paleontology, Eötvös University, Budapest, [email protected]

This meeting was sponsored by: IGCP (International Geoscience Programme), funded by the IUGS (International Union of Geological Sciences) and UNESCO Hungarian Academy of Sciences Hungarian Natural History Museum Natural History Museum of Eötvös University, Budapest Hantken Foundation IGCP National Committee of Austria

Organizers: J. PÁLFY, P. OZSVÁRT, J. HAAS, N. ZAJZON (Hungary) L. KRYSTYN (Austria)

Web site: paleo.cortland.edu/IGCP458

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CONTENTS Welcome Program overview and practical hints List of participants Program of conference day (oral presentations) List of posters Abstracts

2 3 4 7 8 9

Field trip guide Excursion H.1 Stop 1: Kálvária Hill, Tata– a geological park Stop 2: Vár-hegy, CsĘvár Stop 3: Hármashatár-hegy, Buda Hills Excursion H.2 Stop 1: KĘris-hegy, Bakonybél, Bakony Mts References

H1 H3 H3 H9 H18 H20 H20 H23

Field trip in Austria The Triassic –Jurassic boundary in the Northern Calcareous Alps Excursion A.1 Stop 1: Adnet, Tropf Quarry Stop 2: Adnet, Lienbacher Quarry Stop 3: Adnet, Rotgrau-Schnöll Quarry Stops 4–7: Steinplatte Excursion A.2 Stops 1 and 2: Kendelbachgraben and Tiefengraben References

A1 A1 A15 A15 A19 A21 A26 A32 A32 A37

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WELCOME Dear Friend and Colleague, Welcome to the 5th Field Workshop of IGCP 458 Project (Triassic-Jurassic Boundary Events). This meeting is scheduled as the last formal workshop of our project that has been active since 2001. This year’s event is hosted in Hungary and Austria. The two countries share a significant part of their history. Although World War I ended the period of the Austro-Hungarian Monarchy and not long after World War II the two countries ended up on the opposite sides of the infamous Iron Curtain, with Hungary’s recent accession to the European Union our ties are strengthening again. But decades and centuries of human history are dwarfed by the tens and hundreds of millions of years of geological evolution which also show remarkable similarities in the territory of our countries. This field workshop will provide opportunities to compare uppermost Triassic and lowermost Jurassic strata in Hungary’s Transdanubian Range and Austria’s Northern Calcareous Alps. Classical and more recently discovered localities have yielded much new information that provides fresh insights into the end-Triassic events and will surely stimulate discussion among the workshop participants in the outcrops. This workshop concludes a series of field meetings of IGCP 458. I’m sure that all former participants have good memories of these meetings that took us to some of the most outstanding Triassic-Jurassic boundary sections while enjoying a cozy and familiar atmosphere, and challenging discussions in the field as well as in the conference room. Personally, I will always remember weathering a rain storm at St. Audrie’s Bay while studying the first proposed TJB GSSP candidate section, observing a great many Van Houten cycles after driving a great many miles in the Newark Supergroup, negotiating steep mountain trails to TJB outcrops in the majestic Tatra Mts that kept one last TJB section secret under 10 cm of fresh snow, and surprising sunbathers and swimmers by busily hammering at TJ boundary beds beside the sparking blue waters of the Ligurian Sea. Our 2005 field meeting will feature four days in the field in two countries, and a conference day full with 14 oral and 9 poster presentations. I would like to thank many of my friends and colleagues whose hard work has made possible to organize this meeting. I’m grateful to all who contributed to this volume and will be your guides in the field, you find their names in the inside front cover. Special thanks are to Leo Krystyn who has put together the Austrian part of our program, János Haas for his contribution to the Hungarian field trips and Péter Ozsvárt who offered the biggest help in organizing the Hungarian part and editing this volume. And thank you all who have come to make a geological journey from the modest hills of Hungary to the awesome peaks of the Austrian Alps. I wish you a successful and enjoyable meeting.

József Pálfy co-leader of IGCP 458 project

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PROGRAM

PROGRAM OVERVIEW AND PRACTICAL HINTS DATE

PROGRAM AND TIME SCHEDULE

PRACTICAL INFORMATION

DAY 1 Monday September 5

Arrival

Shuttles leave for Tata from Natural History Museum in Budapest at ~2 pm, 4 pm, and 5 pm

DAY 2 Tuesday September 6

Field excursion H1 Leave Tata by bus at 8:30 Arrive back to hotel at ~22:30 Conference dinner & cruise 18:30-21:00

For the field trip, have good footware for walking on steep terrain You may wish to have an extra pair of casual shoes for the evening program Be prepared for a long day

DAY 3 Wednesday September 7

Conference day Morning session starts at 9:00

Meeting room is on the second floor of the east building (across the yard from the west building /reception desk) See detailed program

DAY 4 Thursday September 8

Field excursion H2 Leave Tata by vans and cars at 8:30

Check out and take all your belongings with you After one field stop in the morning, we travel to Hallein (Austria) in the afternoon

DAY 5 Friday September 9

Field excursion A1 Leave from Gasthof by vans and cars at 8:30

DAY 6 Saturday September 10

Field excursion A2 Leave from Gasthof by vans and cars at 8:30

Please note Meal times at Tata Olympic Training Center: Breakfast 7:30 – 9:00 Lunch 12:00 – 14:00 Dinner 18:00 – 19:45

Check out and take all your belongings with you Travel in a vehicle according to your personal arrangement for drop-off for your homeward journey

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LIST OF PARTICIPANTS AMOR, Ken

BLOOS, Gert

BÖHM, Florian

BÖKENSCHMIDT, Sven

BUDAI, Tamás

CSÁSZÁR , Géza

CIARAPICA, Gloria

COHEN, Anthony

DEMÉNY, Attila

FURIN, Stefano

RIVA, Alberto

GOETZ, Annette E.

GOLEJ, Marián

GÖRÖG, Ágnes

GRĂDINARU, Eugen

HAAS, János

HESSELBO, Stephen

KHALIFA, Mohamed

KORTE, Christoph

KOZUR, Heinz

Department of Earth Sciences, University of Oxford U.K. [email protected] Leibniz-Institut f. Meereswissenschaften IfM-GEOMAR Germany [email protected] Hungarian Geological Institute Hungary [email protected] Dipartimento Scienze della Terra, Universitá di Perugia Italy [email protected], [email protected] Institute for Geochemical Research, Hungarian Academy of Sciences Hungary [email protected] Ferrara University, Dipartimento di Scienze della Terra, Italy

Department of Geology and Paleontology, Faculty of Natural Sciences, Comenius University Slovakia [email protected] Department of Geology and Palaeontology, University of Bucharest Romania [email protected] Department of Earth Sciences, University of Oxford U.K. [email protected]

Department of Earth Sciences, University of Oxford U.K. [email protected]

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Staatl. Museum fur Naturkunde, Stuttgart Germany [email protected] Fachbereich Geowissenschaften, Philipps-Universität Marburg Germany [email protected] Hungarian Geological Institute Hungary [email protected] The Open University, Department of Earth Sciences U.K. [email protected]

Ferrara University, Dipartimento di Scienze della Terra Italy [email protected] Institute of Geosciences, Martin-Luther-University Halle-Wittenberg, Germany [email protected] Dept. of Paleontology, Eötvös University of Budapest Hungary [email protected]

HAS-Eötvös University, Research Group for Geology Hungary [email protected] Geology Dept., Faculty of Science, Menoufia University Egypt [email protected] Hungary [email protected]

2005

PROGRAM

KRYSTYN, Leo

KÜRSCHNER, Wolfram

LATHUILIERE, Bernard

LINTNEROVA, Otilia

MACDONALD, Elisabeth

MCROBERTS, Christopher

OZSVÁRT, Péter

PÁLFY, József

PIROS, Olga

REGGIANI, Letizia

RIGO, Manuel

RUCKWIED, Katrin

SIBLÍK, Milos

STANLEY, George

TANNER, Lawrence

TOMAŠOVÝCH, Adam

VON HILLEBRANDT, Axel

VÖRÖS , Attila

VUKS, Valery

WARRINGTON, Geoff

WEISZBURG, Tamás

WILLIFORD, Ken

Palaeontologisches Institut der Universitaet Wien Austria [email protected]

Géologie et Gestion des Ressources Minérales et Energétiques, Université de Nancy France [email protected] University of Birmingham, Dept. of Earth Sciences U.K. [email protected]

HAS-HNHM Research Group for Paleontology Hungary [email protected] Hungarian Geological Institute Hungary [email protected] Dept. of Geology and Paleontology, Padova University Italy [email protected] Institute of Geology ASCR Czech Republic [email protected] Dept. of Biological Sciences, Le Moyne College USA [email protected] TU Berlin, Institut für Angewandte Geowissenschaften Germany [email protected] All Russian Geological Research Institute (VSEGEI) Russia [email protected] Eötvös University, Budapest Hungary [email protected]

Utrecht University, Department of Biology, Section Palaeoecology The Netherlands [email protected] Comenius University, Fac. Natural Sci. Slovakia [email protected]

Deptartment of Geology, State University of New York at Cortland USA [email protected] HAS-HNHM Research Group for Paleontology Hungary [email protected] Dipartimento Scienze della Terra, Universitá di Perugia Italy Institute of Geosciences, Martin-Luther-University Halle-Wittenberg Germany [email protected] University of Montana, USA [email protected] Wuerzburg University, Paleontological Institute Germany [email protected] HAS-HNHM Research Group for Paleontology, Hungary [email protected]

University of Leicester U.K. [email protected]

Department of Biology, University of Washington USA [email protected]

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ZAJZON, Norbert

University of Miskolc, Hungary [email protected], [email protected]

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ZANKL, Heinrich

Fachbereich Geowissenschaften, Philipps-Universität Marburg, Germany [email protected]

2005

PROGRAM

CONFERENCE DAY (WEDNESDAY, SEPTEMBER 7, 2005) Morning session 1 – Chair: S. HESSELBO 9:00 – 9:20

CIARAPICA, G.*, REGGIANI, L., RIGO, M. and ROGHI, G.

New data on bio- and lithofacies variations around the Triassic/Jurassic boundary in the Porto Venere sections (La Spezia, Italy)

9:20 – 9:40

KHALIFA, M. A.

Facies across the Triassic-Jurassic boundary in Libya: Implications for lithostratigraphy, tectonics and depositional history

9:40 – 10:00

MACDONALD, E.C.A.C.

Micropalaontological and ichnological analysis of Triassic/Jurassic boundary sections of SW Britain

10:00 – 10:20

HILLEBRANDT, A. von

The earliest Psiloceras in South America

10:20 – 10:40

COFFEE BREAK

Morning session 2 – Chair: C. MCROBERTS 10:40 – 11:00

GOLEJ, M.

Rhaetian bivalves of Hybe Formation: paleoecology and paleobiogeography

11:00 – 11:20

TOMAŠOVÝCH, A.* and SIBLÍK, M.

Analyzing brachiopod distribution patterns before and after the Triassic-Jurassic mass extinction in the Northern Calcareous Alps (Austria)

11:20 – 11:40

STANLEY, G. D., Jr.

Late Triassic events among reef ecosystems during the latest Triassic interval

11:40 – 12:00

LATHUILIERE, B.* and MARCHAL, D.

Diversity crises of corals from Triassic to Dogger

12:00 – 12:20

KÜRSCHNER, W.

High resolution reconstruction of climate across the T–J transition inferred from palynological evidence

12:20 – 13:50

LUNCH

Afternoon session 1 – Chair: J. HAAS 13:50 – 14:10

TANNER, L. H* and KYTE, F. T.

Iridium enrichment at the Triassic-Jurassic boundary, Blomidon Formation, Fundy Basin, Canada

14:10 – 14:30

DEMÉNY, A.

Stable isotope trends across the Triassic-Jurassic boundary at CsĘvár, Hungary

14:30 – 14:50

WILLIFORD, K. H.* and WARD, P. D.

Biogeochemistry of the Triassic-Jurassic boundary

14:50 – 15:10

COHEN, A. S. and COE, A. L.

Interpreting the marine Os- and Sr-isotope records across the Triassic-Jurassic boundary

15:10 – 15:30

HESSELBO, S.*, MCROBERTS, C. and PÁLFY, J.

Understanding the Triassic-Jurassic boundary events: Recent progress and outstanding problems

15:30 – 15:50

COFFEE BREAK

15:50 – 17:00

Poster session

17:00 – 17:30

IGCP 458 Business Meeting Update on TJB Working Group activities and GSSP selection (G. Warrington) 7

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LIST OF POSTERS BIROĕ, ADRIAN, LINTNEROVÁ, OTÍLIA*, MICHALÍK, JOZEF & SOTÁK, JÁN

Clay mineral distribution across the T/J boundary beds preliminary results from the West Carpathian sections

BÖHM, FLORIAN*, EISENHAUER, ANTON, HEUSER, ALEXANDER

Expected impact of the Triassic-Jurassic Reef crisis on the oceanic calcium and calcium isotope budget

BÖKENSCHMIDT, SVEN & ZANKL, HEINRICH*

Lithology, biostratigraphy and sedimentary petrology of the T-J boundary section in the Steinplatte and Scheibelberg area (Salzburg – Tirol, Austria)

GRĂDINARU, EUGEN

Triassic-Jurassic boundary events in north Dobrogea (Romania) as recorded in basinal marine environments

KORTE, CHRISTOPH*, HESSELBO, STEPHEN P., JENKYNS, HUGH C. & KOZUR, HEINZ W.

Isotope trends at the Triassic/Jurassic transition

MICHALÍK, JOZEF, LINTNEROVÁ, OTÍLIA*, GAħDZICKI, ANDRZEJ & SOTÁK, JÁN

Record of environmental changes in the Triassic/Jurassic boundary interval in the Zliechov Basin, Western Carpathians

OZSVÁRT, PÉTER* & ELIZABETH S. CARTER

Radiolarian faunal change across the Triassic-Jurassic boundary in the CsĘvár section, Northern Hungary

RUCKWIED, KATRIN*, GÖTZ, ANNETTE E. & MICHALÍK, JOZEF

Palynology of the Triassic-Jurassic boundary of the Furkaska section (Tatra Mts., Slovakia) – first results

STANLEY, JR., G. D.*, MACKAY, M. L. & SMITH, P. L.

Paleoautecology of Heterastridium: a globally distributed hydrozoan from upper Triassic terranes of the North American Cordillera

VUKS, VALERY JA.

Triassic/Jurassic boundary in Precaucasus and Mangyshlak

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ABSTRACTS

ABSTRACTS Clay mineral distribution across the T/J boundary beds - preliminary results from the West Carpathian sections BIROĕ, ADRIAN 1, LINTNEROVÁ, OTÍLIA2*, MICHALÍK, JOZEF3 & SOTÁK, JÁN1 1

Geological Institute, Slovak Academy of Science, Severná 5, 974 01 Banská Bystrica, Slovakia, [email protected] [email protected] 2 Comenius University, Faculty of Science, Mlynská dolina, 842 15, Bratislava, Slovakia, [email protected] 3 Geological Institute, Slovak Academy of Science, Dúbravská 9, PO Box 106, 84005 Bratislava, Slovakia, [email protected]

The qualitative and semi-quantitative distributions of clay minerals in the < 2 Pm fraction have been studied in 13 samples of the Furkaska section and in 14 samples of the Široky žlab section. These sections cover the stratigraphic interval from the Norian part of the Carpathian Keuper, Rhaetian Fatra Fm. to Hettangian Kopienec Fm. Mixed-layer illite/smectite (I/S) with 10-20% of smectite interlayers represents more than 80% of the clay-size fraction of all studied samples. The rest consist of illite, chlorite and kaolinite. While distribution of I/S, illite and chlorite do not show any regular pattern, yielding various proportions in individual samples, the kaolinite first appearance was recognized in the T/J boundary beds reaching the maximum content of 10-12% in the Kopienec claystones in both sections. Since kaolinite is considered as a useful palaeoclimatic indicator, its appearance may indicate a change to a more humid climate during lowermost Jurassic in comparison with the Rhaetian stage. Nevertheless, persistent prevalence of I/S (most probably originating from smectitic precursor) in clay-size fractions of both Rhaethian and Hettangian samples suggests that the source material of these sediments was

formed during weathering in seasonally wet and dry climate [1]. However, it should be emphasized that changes in clay mineral assemblages in these typical T/J boundary sections may have been controlled not only by the type of climatic conditions and respective weathering regime but also by changes in depositional conditions and by succeeding diagenetic alteration. Low content of smectite interlayers in I/S is indicative of relatively high diagenetic overprint of investigated sequences, corresponding to approximate burial temperature of 150°C. Instead of commonly encountered tritrioctahedral chlorite, unusual di-trioctahedral high alumina chlorite (sudoite) has been identified in four samples from the interval between beds 387 and 405 of the Furkaska section (Fatra Fm.). It is noteworthy, that it occurs just under and above spherule-bearing beds (400 and 401), which probably represent “event” sediment related to either cosmic impact, or to sediment enriched in volcanic material. However, this assumption will require additional study to assess the relationship between clay mineralogy and the origin of spherule layers.

REFERENCE: [1] Ruffell A., McKinley,J.M and Worden, R.H.(2002) Comparison of clay mineral stratigraphy to other palaeoclimate indicators in the Mesozoic of NW Europe Phil.Trans. R. Soc.Lond. A 360, 675-693.

Expected impact of the Triassic-Jurassic Reef crisis on the oceanic calcium and calcium isotope budget BÖHM, FLORIAN*, EISENHAUER, ANTON, HEUSER, ALEXANDER IFM-GEOMAR, Kiel, Germany; [email protected]

The Triassic-Jurassic boundary event had a significant impact on the ocean carbonate system. This is evident from the carbon isotope record, pCO2 reconstructions, the sudden decline of reef carbonates and lack of reefs during the early

Liassic [1-3]. The global calcium cycle is closely connected to the carbon cycle, because both during continental weathering and marine burial calcium is mainly processed as CaCO3. The strong increase of atmospheric CO2 at the T-J 9

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boundary should have strongly increased the continental weathering flux of both Ca and carbonate ions due to CO2 induced silicate and carbonate weathering. At the same time the CAMP volcanism probably provided enhanced Ca input to the oceans by increased SO2 weathering. CO2 weathering fluxes have little impact on the oceanic Ca concentration, because Ca2+ and CO32- are delivered to the oceans in equal amounts and any excess of these ions is quickly precipitated and buried as CaCO3 [4]. As the Ca concentration in the oceans is about two orders of magnitude greater than the carbonate ion concentration, there is also no expected response of calcium to the decline of reef carbonate production, as long as there is an efficient CaCO3 buffer in the oceans. Less carbonate production is buffered by decreased dissolution and enhanced burial due to rising CaCO3 saturation (CO3 concentration). This buffer is represented in post-Triassic oceans by deep-sea carbonate sediments, and may have been less effective during the early Liassic. A more promising possibility to increase marine Ca concentrations is to release calcium by sulfuric acid weathering

during volcanic activity. This Ca flux is not coupled to carbonate and therefore effectively increases marine Ca concentrations. At the same time the rising CaCO3 saturation would lead to decreased marine dissolution and consequently to a strong decline of the marine carbonate ion concentration. Independent of the mechanisms discussed above, rising marine calcium concentrations during the early Liassic would be reflected in decreasing calcium isotope ratios [5]. The lack of reef carbonate deposition during the early Liassic and the low sea-level during this time probably caused a decrease of dolomite formation. On the long term dolomite frequency declined by about 30% from the Triassic to the Liassic [6]. As dolomite formation provides a source of isotopically light Ca to the ocean [7], reduced dolomite formation would lead to reduced Ca concentrations and increased 44 Ca/40Ca ratios in the Liassic oceans. With that, a calcium isotope record across the TriassicJurassic boundary could be expected to show an initial decline in 44Ca/40Ca ratios followed by a rising trend.

REFERENCES: [1] Pálfy, J., Demény, A., Haas, J., Hetényi, M., Orchard, M.J., Vetö, I. (2001) Carbon isotope anomaly and other geochemical changes at the Triassic-Jurassic boundary. Geology 29, 1047-1050. [2] Beerling, D.J., Berner, R.A. (2002) Biogeochemical constraints on the Triassic-Jurassic boundary carbon cycle event. Global Biogeochem. Cycles 16, doi: 10.1029/2001GB001637. [3] Hautmann, M. (2004) Effect of end-Triassic CO2 maximum on carbonate sedimentation and marine mass extinction. Facies 50, 257-261. [4] Berner, R.A. (2004) A model for calcium, magnesium and sulfate in seawater over Phanerozoic time. Amer. J. Sci. 304, 438453. [5] De La Rocha, C.L., DePaolo, D.J. (2000) Isotopic evidence for variations in the marine calcium cycle over the Cenozoic. Science 289, 1176-1178. [6] Sun, S.Q. (1994) A reappraisal of dolomite abundance and occurrence in the Phanerozoic. J. Sed. Res. A64, 396-404. [7] Heuser, A., Eisenhauer, A., Böhm, F., Wallmann, K., Gussone, N., Pearson, P. N., Nägler, T. F., Dullo, W.-Chr. (2005): Calcium Isotope (G44/40Ca) Variations of Neogene Planktonic Foraminifera. Paleoceanography 20, PA2013, doi:10.1029/2004PA001048.

Lithology, biostratigraphy and sedimentary petrology of the T-J boundary section in the Steinplatte and Scheibelberg area (Salzburg – Tirol, Austria) BÖKENSCHMIDT, SVEN & ZANKL, HEINRICH 1

Geological Institute, University of Marburg, [email protected]

In the Steinplatte – Scheibelberg area the upper Triassic basin facies of the Kössen Formation shows a continuous transition into the lowermost Jurassic beds of the Kendlbach formation, as well a basin facies. Two outcrops have been investigated, one on the north slope of the Scheibelberg, another at the Kammerköhr Alpe. The profile indicates an increasing influence of clay minerals that interrupt the carbonate production on the top of the Kössen limestones (Rhaetian). Marly bituminous limestones of 0.5 m thickness include a bivalve 10

fauna (”Cardinia”) and a bone-bed with fish remains. The clay minerals consist – beside illite and smektite – mainly of kaolinite that has derived from a major terrestrial erosion event. These clay minerals caused an abrupt facies change in the T-J sequence within the Steinplatte-Scheibelberg basin. The mainly limestones at the base of the Kendlbach formation are followed by marly clay beds of about 2 m thickness. The spectrum of clay minerals changes towards the top from a kaolinite-illite-smektite into a smektite

2005 dominated assemblage; this could be interpreted as an increasing water depth due to a sea level rise. The kaolinite was washed from a terrestrial environment nearby into the basin whereas the smektite documents an increasing distance to the source area. Microspores were deposited together with the clay in the pelitic sediments. Beside species that have a wide stratigraphic range, there are a few species which characterize the lower Hettangium. Comparable to the microflora described by Karle 1984 from the Fonsjoch in the Steinplatte-Scheibelberg sections Zebrasporites interscriptus, KLAUS 1960 and Concavisporites cassexinus, NILSSON 1958 are present as well. Morbey 1975 found in the FG-Subzone of the Kendlbach-Graben Kraeuselisporites reissingeri with a drastically increasing number of spores comparable to the Steinplatte-Scheibelberg sections. Taking the results of the palynological studies and the additional biostratigraphic information from the Kössen formation into consideration the T-J boundary could be located at the base Kendlbach formation or within the

ABSTRACTS first 0.30 m of it. The marly clay sequence of the Kendlbach formation is capped by a crinoidal limestone of 1.0 m thickness, the bioclasts are redeposited at a distal part of a submarine slope. These crinoidal limestones are overlain by cherty nodular limestones of the Scheibelberg formation. Kammerkarites haploptychus (Waehner) near the base of the Scheibelberg limestone indicates an age of lower to middle Hettangium. Conclusions: The Steinplatte-Scheibelberg basin facies of the Kendlbach formation shows within the T-J boundary section a continuous marine development. The T-J boundary is located at the base of the Kendlbach formation or within the lowest 0.30 m of marly limestones, probably below the bonebed and coquina layer. The carbonate production of the Kössen formation is interrupted by an increasing input of terrigenous clay (kaolinite, illite and smektite) indicating a short-period climatic event of intensified weathering and transportation of fine material from the surrounding continental environment.

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New data on bio- and lithofacies variations around the Triassic/ Jurassic boundary in the Porto Venere sections (La Spezia, Italy) CIARAPICA, GLORIA1*, REGGIANI, LETIZIA2, RIGO, MANUEL3 & ROGHI, GUIDO4 1

Dipartimento di Scienze della Terra, University of Perugia, Italy, [email protected] Dipartimento di Scienze della Terra, University of Perugia, Italy, [email protected] 3 Dipartimento di Geologia, Paleontologia e Geofisica, University of Padua, Italy, [email protected] 4 Institute of Geosciences and Georesources, C.N.R. and Dipartimento di Geologia, Paleontologia e Geofisica, University of Padua, Italy, [email protected] 2

The lowest part of the Mesozoic La Spezia succession (eastern Liguria, Northern Apennines) contains the Triassic /Jurassic boundary (TJB) in the uppermost part of the La Spezia Fm., in particular in the Portovenere Limestones member. The Late Triassic and the Early Jurassic beds, outcropping in an upsidedown sequence, are well exposed in the two sections of Portovenere and Muzzerone. The Portovenere Limestones are thin-bedded dark limestones, 70 m thick, deposited in a basin often in anaerobic conditions, connected to the adjacent carbonate platform by a ramp [1]. They display slump structures, marly intervals, some graded beds interpreted as storm layers. The main fossil content is due to foraminifers and bivalves. The sedimentologic and lithostratigraphic studies carried out outline some facies changes along the succession, consisting on increase in clay or decrease in carbonate input inside the basin towards the upper part of the succession. The slump deformations and the storm layers decrease toward the top, indicating that the depositional environment passed from a middle to a distal ramp and the depth was increasing. The uppermost part of the Portovenere Limestones is represented by the 7-m-thick Grotta Arpaia interval, which is composed of black shales with thin carbonate beds. This interval contains the TJB in the upper part. Immediately below the Grotta Arpaia interval, some carbonate beds display small build-ups, only 30 cm high, made up of serpulids and small bivalves (Dimyodon intusstriatus), contained in 5060 cm of succession. This horizon is documented in both the studied sections, as well as in the Tino Island (2 km to the south) and in the Valdipino area (10 km to the north) with the same thickness. In this horizon, Late Triassic

foraminifers are present (Aulotortus friedli, Aulotortus sinuosus, Glomospirella hoe). The succession of Grotta Arpaia begins with 30 cm of hard shales with small quartz grains and it consists of 7 m of repetitions of shales and massive marly limestones, two-three cm thick, made up of mudstone and scattered wackestones, packstones being very rare. The foraminifers found in this interval are Auloconus permodiscoides and Aulotortus sp. The bedding surfaces contain many ichnofossil trails, of various size from 2-3 mm up to 2-3 cm in diameter. Their presence indicates a low sedimentation rate. Two thicker carbonate beds (10 and 18 cm respectively) represent a marker horizon that can be followed in all the outcrops of the Grotta Arpaia beds. The thickest one is made up of wackestone packstone with rounded recrystallized ghosts of fossil remains, probably due to calcitized radiolarians. Some siliceous radiolarians were described in the Portovenere section [2]. In this bed, at the Muzzerone section, the conodont species Misikella ultima and Misikella posthernsteini occur. Palynological investigations around the TJB for both the Grotta Arpaia and Muzzerone sections are in progress. On the top of this bed, which is the last containing Triassic conodonts, hard laminated siltstones appear, with a thickness of 80 cm. They contain quartz grains in a carbonate matrix. The planar laminas are due to thin layers of quartz grains, less than 100 µm thick. In the siltstone and in the overlying carbonate beds, conodonts or other Triassic fossils are absent. This horizon probably corresponds to the extinction at the TJB. The siltstones represent a special event of quartz input inside the basin that never occurred below the Grotta Arpaia interval. It could be due to a sea-level fall that caused a major erosion activity in some continental areas surrounding the basin.

REFERENCES: [1] Ciarapica, G., Passeri L. (2005) Late Triassic and Early Jurassic sedimentary evolution of the Northern Apennines: an overview. Boll. Soc. Geol. It., 124, 189-201. [2] Ciarapica, G., Zaninetti, L. (1982) Faune a radiolaires dans la sequence Triasique/Liasique de Grotta Arpaia, Portovenere (La Spezia), Apennin Septentrional. Revue de Paléobiologie, 1, 165-179.

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Interpreting the marine Os- and Sr-isotope records across the Triassic-Jurassic boundary COHEN, ANTHONY S. & COE, ANGELA L. Dept. of Earth Sciences, The Open University, Milton Keynes, MK7 6AA, U.K. [email protected], [email protected]

The Sr- and Os-isotope compositions of seawater have varied over geological time in response to the fluctuating balance between the major inputs of these elements to the oceans. In both cases, the two major inputs are the chemical weathering of the continental crust and the hydrothermal alteration of juvenile oceanic crust at mid-ocean spreading ridges. Because the contribution from hydrothermal alteration is likely to have been constant on relatively short timescales of a few Ma or less (and perhaps over much longer periods as well), it follows that short-term or sudden changes in the seawater Srand Os-isotope compositions are likely to have been caused by abrupt changes in the weathering flux from the continental crust. Thus, since the continental weathering flux responds to changing environmental and climatic conditions, the analysis of records of the seawater Sr- and Osisotope compositions can be used to provide valuable information about the nature of past environmental change. This presentation is a summary of a detailed analysis of the changing seawater Sr- and Os-isotope compositions across the Triassic-Jurassic boundary (Cohen and Coe, in prep.). The changes are compared with a similar pattern of changes occurring ~17 Ma later in the Toarcian. We have used results obtained from a number of published studies; data for the seawater Sr-isotope composition for this period are from [1-2] while the seawater Osisotope records are from [3-5]. The overall form of the seawater Sr-isotope curve from the late Triassic to the late middle Jurassic is one of a continuously decreasing 87 Sr/86Sr ratio that commenced close to the Norian-Rhaetian boundary, and continued to do so for a period of ~50 Ma until it reached, in the Oxfordian, the lowest value recorded for the Phanerozoic. There were, however, two major perturbations to this ~50 Ma decreasing trend

that each involved a temporary but significant increase in the seawater 87Sr/86Sr ratio. The first occurred close to the Triassic-Jurassic boundary ~200 Ma ago, while the second occurred in the Toarcian ~183 Ma ago. Both of these perturbations to the changing Sr-isotope composition of seawater also coincided with marked changes in the seawater Os-isotope composition, with major perturbations to the marine G13C record, and with significant mass extinctions. The seawater Os-isotope composition registered a sharp decrease in its 187Os/188Os ratio in the late Triassic that was followed by unusually unradiogenic (i.e. low) ratios for the entire duration of the Hettangian. Following its sudden increase in the late Rhaetian, the seawater 87 Sr/86Sr ratio levelled off during the Hettangian but started to decrease once more at the end of this stage, whilst the seawater 187Os/188Os ratio showed a pronounced increase at the end of the Hettangian. We explain these observations as being the result of a major perturbation to global climate that caused greatly increased precipitation and runoff. The vigorous hydrological cycle resulted in the rapid weathering and erosion of the CAMP immediately after its emplacement, as well as increased rates of weathering and erosion of other crustal lithologies. The patterns of change in the seawater Os- and Sr-isotope records that occurred in the late Triassic-early Jurassic show many similarities with those that took place in the Toarcian ~17 Ma later, which overlapped the eruption of the Karoo-Ferrar igneous province. The clear resemblance between the observations for both the TriassicJurassic boundary event and for the Toarcian event suggests strongly that similar controlling processes have operated at different times of Earth history.

REFERENCES: [1] Jones, C. E. et al., (1994) Strontium isotopes in Early Jurassic seawater. Geochim. Cosmochim. Acta 58, 1285-1301. [2] Korte, C. et al., (2003) Strontium isotope evolution of Late Permian and Triassic seawater. Geochim. Cosmochim. Acta 67, 47-62. [3] Cohen, A. S. et al., (1999) Precise Re-Os ages of organic-rich mudrocks and the Os isotope composition of Jurassic seawater. Earth Planet. Sci. Lett. 167, 159-173. [4] Cohen, A. S. and Coe, A. L. (2002) New geochemical evidence for the onset of volcanism in the Central Atlantic Magmatic Province and environmental change at the Triassic-Jurassic boundary. Geology 30, 267-270. [5] Cohen, A. S. et al., (2004) Osmium isotope evidence for the regulation of atmospheric CO2 by continental weathering. Geology 32, 157-160

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Stable isotope trends across the Triassic-Jurassic boundary at CsĘvár, Hungary DEMÉNY, ATTILA Institute for Geochemical Research, Hungarian Academy of Sciences H-1112 Budapest, Budaörsi út 45, Hungary, [email protected]

Pálfy et al. (2001) reported a significant į13C shift occurring in the Triassic-Jurassic (T-J) boundary layers at CsĘvár. Subsequent studies in other sections world-wide have verified the existence of carbon isotope excursions in the T-J boundary layers that can be used as a global correlation tool. These studies have identified several shifts and peaks before, at and after the actual boundary event that indicates prolonged instability of environmental conditions and/or superposition of multiple processes. Among several processes capable of producing such į13C changes (productivity collapse, volcanism, impact, methane release), sudden dissociation of deep-sea methane-hydrates seems to be the most viable process. However, high-resolution records have not been available to date that could be used to test this model and further clarify the possible mechanisms. This study presents a detailed stable

isotope geochemical investigation of the CsĘvár section. The first task was to determine the extent of late-stage (e.g. diagenetic) alteration that could have modified the original isotopic signal. After resampling the main section, new isotopic analyses on bulk rock samples as well as calcite veins revealed alteration effects. However, a parallel, closely spaced alternative section exposing the T-J boundary interval at CsĘvár appears undisturbed by alteration. The detailed analysis of this new section revealed strong į13Cį18O correlation that may not be related to diagenesis. The underlying phenomena are interpreted as episodic, short-term perturbations of the global carbon cycle, likely due to methane release from gas-hydrate dissociation induced by rapid climatic events. Warming in excess of +10°C is calculated on the basis of the measured į18O values.

Rhaetian bivalves of Hybe Formation: paleoecology and paleobiogeography GOLEJ, MARIÁN Department of Geology and Paleontology, Faculty of Natural Sciences, Comenius University, Mlynská dolina, 842 15, Bratislava, Slovakia , e-mail: [email protected]

During two years of research (2003-2004) at the Hybe locality 1100 fossil remains, mainly bivalves and some gastropods, were obtained from the Hybe beds (Hronic Superunit). Two profiles, namely Kantorská pit and Simkovicsova pit were sampled bed by bed. The analysis of species determined shows, that assemblages which evolved in the marine environments were strongly controlled by the substrate character. Two important associations were recognized. The first one which evolved on the firm and stable substrate where the shell production exceeded the rate of sedimentation. Was represented by Actinostreon haidingerianum/Chlamys simkovicsi association, Actinostreon haidingerianum/Chlamys sp. association, "Parallelodon hettangiensis"/Plagiostoma punctatum association and Plagiostoma subvaloniense/ Atreta "intusstriata" association. The time interval represented by these rocks is longer, rather than in the latter example. The second main association evolved on the soft bottom and is represented by Modiolus "hybbensis" and Chlamys valoniensis association. The facies is mainly represented by tempestites, and the fossil record preserved reflects one contemporaneous benthic 14

association. Both environments were inhabitated by monotonous species group (mainly with opportunistic and ecologically tolerant species). Morphologically adapted forms evolved with the change of substrate character. In the whole association epifaunal types of suspension feeding bivalves are dominant. The semiinfaunal type of group is represented by free mobile suspension feeders only. The infaunal type is represent by two deposit feeding species belonging to the Nuculidae only. Its shows, that the stable and firm bottom conditons were unsuitable place for their life. The associations recognized fully resembles the Oxytoma biofacies of Eiberg Member (the upper part of the Kössen Formation). One new species Camptonectes (Camptochlamys?) sp. nov. is described, which represents a transitional form to the Camptonectes and Camptochlamys subgenera. For the first time antimarginal microsculpture on the shells of „Chlamys (Chlamys)“ simkovicsi (Goetel, 1917) and „Chlamys (Chlamys)“ valoniensis (Defrance, 1825) was observed. The fossil Pleuroacanthites ex. gr. biformis (J. Sowerby, 1831) described as ammonite from this locality [1] is in this work

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ascribed to the rarely and untypically spired gastropod Kokenella costata (Münster, 1841), which was found two times during two centuries at the Hybe locality only. The revision of the original W. Goetel´s collection in Cracow (Poland) brought some new information to the determination of samples therefore it is possible, that all samples of this author came from the Simkovicsova section. The association is very similar to those known from Austria (the Kössen Formation and the Zlambach beds) and England (Westbury and Lilstock formations). Therefore, the connection

between these areas must have existed. These mainly opportunistic and ecologically tolerant species (as relics of formerly very diversified associations) immigrated at the end of the Triassic to new epicontinental seas westwards along the Armorician Massive. In the Lower Liassic after the new onset of carbonate deposition (mainly since the Sinemurian) another situation happened. Diversified associations from shallow epicontinental seas immigrated into the faunal - depleted (after upper Triassic extinction) environments in the Western Carpathians.

REFERENCE: [1] Rakús M., 1992: Cephalopod fauna from Hybe member of Kössen Fm. in Choè nappe (West Carpathians). Západné Karpaty, Paleontológia, 16, 35-42.

Triassic-Jurassic boundary events in north Dobrogea (Romania) as recorded in basinal marine environments GRĂDINARU, EUGEN Faculty of Geology and Geophysics, University of Bucharest, Bd.Bãlcescu Nicolae 1, RO-010041 Bucharest, Romania, E-mail: [email protected]

Triassic and Lower Jurassic sedimentary sequences are well preserved in the Tulcea Unit of the North Dobrogean Orogene. Due to the outcrop conditions, the lithologic and biotic events around the Triassic-Jurassic boundary can be examined only in the basinal sedimentary sequences from the CataloiFrecaĠei-Trestenic Zone in the western, innermost part of the Tulcea Unit. In this zone, the sedimentation of the Cataloi Formation, which is the most representative lithostratigraphic unit of the basinal facies, lasted a long time-interval, from Upper Anisian till the top of the Norian. This litostratigraphic unit is a dark-gray marly sequence with subordinately interbedded dark-gray limestones. The Cataloi Formation grades upwards to the FrecaĠei Sandstone which extends in the RhaetianHettangian time-interval. The passage from the Cataloi Formation to the Frecaþei Sandstone is exposed in an outcrop located at 1.5 km east of the Frecaþei village. This section, having over 130 m in thickness, shows a lithostratigraphic continuity across the Triassic-Jurassic boundary, which is marked by a remarkable gradual transition from the Upper Triassic basinal carbonate sedimentation to the Lower Jurassic terrigenous sedimentation. The Rhaetian sequence includes an alternation of gray silty marls and marly siltstones with interbedded layers of Norigondolella

steinbergensis-bearing reddish-gray nodular limestones, grading upwards to calcareous siltstones, and closes with a 4.5 m thick package of Otapiria marshalli alpina-bearing coquinoid calcareous siltstones. The Hettangian sequence includes thickbedded, fine-grained gray calcarenaceousquartzose sandstones and siltstones with rare layers of gray mudstones. A level with Caloceras johnstoni is occurring in the basal part of the sequence. Starting with the Sinemurian up to the Pliensbachian, the Poüta Sandstone is made up of graded-bedded, greenish gray fine-grained argillaceous sandstones and siltstones with rare dark-black clay intercalations. Layers of hard, nodular dark-black calcareous siltstones are interspersed in the upper part of the Sinemurian sequence. The hemipelagic deposits of the Poüta Sandstone are coeval and closely associated to the outer-fan turbidites of the Nalbant Formation. Concluding, the Triassic-Jurassic boundary interval in the Cataloi-FrecaĠei-Trestenic Zone in the westernmost part of the Tulcea Unit records in the Rhaetian-Hettangian time-interval a gradual transition from a basinal carbonate sedimentation to a hemipelagic sedimentation. The registered biotic events are closely related to the basinal sedimentary conditions which evolved around the Triassic-Jurassic boundary interval in the innermost part of the Tulcea Unit.

REFERENCES: [1] Grădinaru, E. (1984) Jurassic rocks of North Dobrogea. A depositional-tectonic approach. Rev. Roum. Geol. Geofiz. Geogr., Ser. Geol., 33, 61-72.

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[2] Grădinaru, E. (2000) Introduction to the Triassic geology of North Dobrogea. Field Trip Guide, Workshop of the LowerMiddle Triassic (Olenekian-Anisian) Boundary, 7-10 June 2000, Tulcea, Romania, 5-18.

Facies across the Triassic-Jurassic boundary in Libya: implications for lithostratigraphy, tectonics and depositional history KHALIFA, M. A. Geology Dept., Faculty of Science, Menoufia University, Shiben El Kom, Egypt, e-mail: [email protected]

The Triassic-Jurassic boundary in Libya shows different nature of contacts from south to north direction. In southeast of Libya at Al Kufra Basin, the Triassic and Jurassic rocks are missed like the southwest corner of Egypt at Gabal Al Awaynat. In this area the carboniferous Az Zalamah Formation unconformably underlies the Lower Cretaceous El Burg Formation. The missing of Triassic-Jurassic rocks may refer to the east-west tectonic uplift occurring in southern Libya in general and southern Tethys in particular. Northwestwards of Al Kufra Basin, the Triassic rocks are represented by coarse clastic rocks which cannot be differentiated from Jurassic facies. Further northwestwards at Gabal Gharian and basinwards, the Upper Triassic Bu Sceba Formation that comprises of cross-bedded,

red to brownish sandstone with thin interbeds of pebbly conglomerate exhibits truncation with the overlying Lower Jurassic buff to light gray dolomitic limestone of Bu Gheilan Formation. This facies association and nature of contact at Triassic-Jurassic boundary is similar to other places in southern Tethys margin as recorded in Jordan and Saudi Arabia. The facies of Upper Triassic in southern Libya are mostly braided streams; they changed northwestwards to marginal marine to flood plain claystone. While the Lower Jurassic facies consist of dolmitic limestone with interbeds of pelletal and oolitic limestone, this indicates sudden transgression occurred due mass extinction at the end of Triassic time.

Isotope trends at the Triassic/Jurassic transition KORTE, CHRISTOPH *1, HESSELBO, STEPHEN P.1, JENKYNS, HUGH C.1 & KOZUR, HEINZ W.2 1

Department of Earth Sciences, University of Oxford, Parks Road, Oxford, OX1 3PR, UK; [email protected]; [email protected]; [email protected] 2 RézsĦ u. 83, H-1029 Budapest, Hungary; [email protected]

Isotope investigations are currently in progress for three different British (Lavernock Point, St. Audrie’s Bay, Watchet) and the Pignola (Lagonegro Basin, Italy) Triassic/Jurassic transition sections. For the British sections G13C and G18O values were established for low-Mgcalcitic oysters. 87Sr/86Sr- and Mg/Ca-ratio analyses for these samples are in preparation. Low-Mg-calcitic fossils are particularly suitable for such studies because this CaCO3 phase is the most resistant to diagenetic alteration, thus minimizing the resetting of the primary geochemical signals [1]. Nevertheless, every fossil will be screened by chemical and optical techniques to evaluate the isotope data. These analyses are currently in progress. However, the carbon-isotope trend for the low-Mg-calcitic oysters follows the decrease of the main G13Corg excursion at the Triassic/Jurassic boundary [2]. The investigated part of the Pignola section comprises the latest Norian, Rhaetian and earliest 16

Jurassic [3]. The test sampling started at the Norian-Rhaetian boundary sensu Kozur (1996), Orchard & Tozer (1997), Bachmann & Kozur (2004), Kozur & Bachmann (2005), Krystyn & Kürschner (2005) at the FAD of Misikella posthernsteini (=base of the CochlocerasParacochloceras fauna of the C. suessi Zone) [4-8]. Detailed bio- and chemostratigraphic work is currently in progress and here we present the first carbon-isotope results for whole rock carbonates from the uppermost Triassic. The G13C curve starts at 1.5‰ around the Norian– Rhaetian boundary. This value is somewhat lower than our numerous Norian data points (typically 2–3‰) and is also lower than the value of ~2.3‰ registered immediately below the radiolarites that begin within the lower M. ultima Zone (lower part of upper Rhaetian). Thus, a slight minimum may be present around the Norian–Rhaetian boundary, but this must be confirmed by further data acquisition. The base

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of the Liassic (Jurassic) lies within the radiolarite, from which we do not yet have any detailed biostratigraphic data. Two G13C minima are present in the lower 25 m of the radiolarite,

which will be dated by radiolarians and conodonts.

We acknowledge the Deutsche Akademie der Naturforscher Leopoldina (BMBF-LPD 9901/8-116) for supporting this project financially.

REFERENCES: [1] Veizer, J., Ala, D., Azmy, K., Bruckschen, P., Buhl, D., Bruhn, F., Carden, G.A.F., Diener, A., Ebneth, S., Goddéris, Y., Jasper, T., Korte, C., Pawellek, F., Podlaha, O.G. and Strauss, H. (1999) 87Sr/86Sr, G13C and G18O evolution of Phanerozoic seawater. Chem. Geol. 161, 59-88. [2] Hesselbo, S.P., Robinson, S.A., Surlyk, F. and Piasecki, S. (2002) Terrestrial and marine extinction at the Triassic-Jurassic boundary synchronized with major carbon-cycle perturbation: A link to initiation of massive volcanism? Geology 30, 251-254. [3] Amodeo, F., Molisso, F., Kozur, H., Marsella, E. and D’Argenio, B. (1993) Age of transitional beds from «cherty limestones» (calcari con selce) to «radiolarites» (scisti silicei) in the Lagonegro domain (Southern Italy). First evidence of Rhaetian conodonts in peninsular Italy. Boll. Serv. Geol. Italia. 110, 3-22. [4] Bachmann, G.H. and Kozur, H.W. (2004) The Germanic Triassic: correlations with the international scale, numerical ages and Milankovitch cyclicity. Hallesches Jahrb. Geowiss. B 26, 17-62. [5] Kozur, H. (1996) The position of the Norian-Rhaetian boundary. In: Jost Wiedmann Symposium, Abstracts. Ber.-Rep. Geol.Paläont. Univ. Kiel 76, 27-35. [6] Kozur, H.W. and Bachmann, G.H. (2005) Correlation of the Germanic Triassic with the international scale. Albertiana 32, 2135. [7] Krystyn, L. and Kuerschner, W.M. (2005) Biotic events around the Norian-Rhaetian boundary from a Tethyan perspective. Albertiana, 32, 17-20. [8] Orchard, M.J. and Tozer, E.T. (1997) Triassic conodont biochronology, its calibration with the ammonoid standard, and a biostratigraphic summary for the western Canada sedimentary basin. Bull. Canad. Petrol. Geol., 45(4), 675-692.

High resolution reconstruction of climate across the Triassic–Jurassic transition inferred from palynological evidence KÜRSCHNER, WOLFRAM M. Section Palaeoecology, Laboratory of Palaeobotany and Palynology, Utrecht University, Budapestlaan 4, 3584 CD Utrecht, NL. [email protected]

The end–Triassic is characterized by one of the five big Phanerozoic mass extinctions in the marine fossil record. The possible mechanisms that are proposed to explain the end–Triassic mass extinction are diverse and range from catastrophic to gradual processes. Climate change scenarios that have been put forward include both, a global cooling as a result of volcanism or the opposite, global warming as a result of volcanic CO2 outgassing or methane release. Previous climate reconstructions are hampered by a lack of a rigorous stratigraphic framework and/or resolution. Here we present the preliminary results of a reconstruction of the climate across the Triassic–Jurassic boundary inferred from palynological evidence. A high resolution quantitative palynological study has been carried out at the Tiefengraben section (Northern Calcareous Alps, Austria). Principal component analysis of high resolution Triassic/Jurassic pollen and spore spectra reveals the order of pollen and spore taxa alongside environmental gradients and subsequently interpretation in terms of climate history. Generally, the climate changes across the Tr-J boundary from semi-arid subtropical with

pronounced seasonality to a warm tropical and humid conditions. Sample scores on the first and second ordination axes allows the quantification of relative temperature and humidity trends over the Tr-J transition. The temperature curve indicates an abrupt warming in the latest Triassic concomitant with the initial carbon-isotope excursion. The maximum warming is followed by long term cooling in the second part of the transitional interval. With regard to precipitation a short term wet spell followed by dryer conditions coincide with the initial carbon isotope excursion. Predominantly wetter climate prevailed through the transitional interval and continues with some dryer phases into the lower Hettangian. Abrupt climate warming associated with wet and dry spells coincides with the initial negative isotope excursion. Climatic extremes may be the result of the enhanced (super) greenhouse effect induced by methane release from clathrates and/or volcanic CO2 outgassing. The succeeding cooling, in turn, may have resulted from a fading greenhouse effect after methane, oxidized to CO2, was sequestered in the sedimentary carbon cycle.

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Diversity crises of corals from Triassic to Dogger LATHUILIERE, BERNARD*1, MARCHAL, DENIS 2 1

UMR CNRS 7566, (G2R), Université de Nancy I, BP 239, F 54506 Vandoeuvre-lès-Nancy cedex; [email protected] 2 Petrobras Energia Venezuela; [email protected]

Depending on authors, organisms or methods of calculation, the Triassic-Jurassic crisis may appear as an artefact or as the first mass extinction in the history of life. This amazing contradiction clearly demonstrates the need for complementary investigations. Recent reviews on the Triassic-Jurassic mass extinction refer to reefs rather than coral taxa. The aim of this communication is to provide an update on the diversity of coral genera during the Triassic and Liassic, to propose diversity, extinction and origination curves for genera over this period, and to show how coral diversity is linked to the development of reefal environments. Material and methods: This work represents a compilation of bibliographical data. Data for the Triassic are based mainly on two previous studies [1-2] which have been completed by [3] and more detailed articles. For the Jurassic, data are based on an exhaustive collection of objective synonymic lists of species. The taxonomic work of revision is less advanced than for the Triassic. Consequently, the uncertainties are greater for the Jurassic. Two levels of confidence are proposed for the data, allowing two evaluations of diversity. An early stage of this compilation was presented in [4]. The results have been plotted on various graphs; including direct view of generic diversity as a function of stages, number of originations per stage and number of extinctions per stage. In order to avoid bias due to the different durations of stages or to the contemporaneous known absolute diversity, rough data were also weighted. The present state of knowledge of corals does not allow to assume an ideal situation where genera would be holophyletic. Nevertheless, we believe that the great instability of generic characters in corals often leads to iterative evolution [5]. Consequently, the amplitude of diversity variations is probably minimized by the use of current genera which in many cases reflect only grades. Fig. 1 shows the chronological relations between extinctions and originations based on minimal evaluation curves. Genera have been distributed in morphological categories to better understand the evolution of morphological spaces during these times. Results: Two coral extinction events clearly appear. One is Late Rhaetian, the other is Late Pliensbachian. Both are confirmed regardless of the method of calculation. As noted by Bambach et al. [6] based on non-coral data, the Rhaetian extinction appears also as a decrease or at best a stagnation of originations. Three origination 18

maxima are pointed. The first one, Norian, appears as a by-product of a long duration of the stage. Hettangian appears as a short stage in which a recovery quickly happened after survival. Pliensbachian appears also as a stage of extensive recovery. Toarcian obviously requires more studies, but already appears as a probable period of recovery after the end-Pliensbachian extinction. The Norian-Rhaetian and Bajocian coincide with the development of highly integrated colonial structures while the Pliensbachian maximum coincides with an major increase in solitary corals. Discussion: The instability of taxonomy in corals is probably the first limitation to interpret these results. The extensive taxonomic revision of Bajocian corals from France based on morphometric studies [7] gives a unique reference to evaluate the order of magnitude of uncertainties in counting the generic diversity from literature. It is close to 50%. This could weaken the interpretation of the Pliensbachian event but the Rhaetian extinction still remains valid. Nevertheless, high and low evaluations show identical trends. Consequently, an extinction at the end of the Pliensbachian (or at the beginning of the Toarcian) is highly probable and was previously recognised for other invertebrates. The development of highly integrated taxa (meandroid and thamnasterioid) is linked to the development of reefal environments (Rhaetian, Bajocian). The Rhaetian extinction corresponds to the collapse of Tethyan reefal ecosystems. Starting from Hettangian, reefs do occur (e.g. [8]) but they are generally small, scattered and limited at a very northern paleolatitude (30° and more). Their distribution in the only region of Tethys in communication with polar waters gives strength to the hothouse climate hypothesis [911]. As for every other mass extinctions, reefal ecosystems are among the most sensitive indicators of global crises. Nevertheless, among the various causes invoked for the TriassicJurassic crisis, corals allow to discard an interpretation according to which sea-level would be the main control. Coral reefs have shown during the Quaternary their capability to face much greater sea-level changes than that we could expect at the Triassic-Jurassic boundary. This contribution was carried out as a part of the project “effets du climat sur la biodiversité et les transferts sédimentaires au Jurassique et au Crétacé” within “Eclipse” Program of the CNRS

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. REFERENCES: [1] Roniewicz E. & Morycowa E. (1989) Triassic scleractinia and the Triassic/Liassic boundary. Mem. Ass. Australas. Paleontols 8, 347-354 [2] Riedel, P. (1991) Korallen in der Trias der Tethys : Stratigraphische Reichweiten, Diversitätsmuster, Entwicklungstren Mitt. Ges. Geol. Berbaustud. ôsterr. Wien, v.37, 97-118. [3] Marchal D. (1991) Répertoire objectif des coraux du Trias, Dipl. sup. Nancy, 80 pp. [4] Lathuilière B. & Marchal D. (2005) Crises de diversité des coraux du Trias au Dogger. Colloque l'Hettangien à Hettange, de la science au patrimoine, Hettange, Univ. H. Poincaré, Nancy 1. 27-32. [5] Lathuiliere B.(1996) Is morphology a good way to understand the evolution of corals? Paleontological Soc. Papers, n°1, 81105. [6] Bambach et al (2004) Origination, extinction and mass depletions of marine diversity, Paleobiology, 30(4), 522-542 [7] Lathuilière B. (2000) Les coraux constructeurs du Bajocien inférieur de France. 2ème partie. Geobios 33,2, 153-181 [8] Elmi S. (1990) Stages in the evolution of late Triassic and Jurassic carbonate platforms : the western margin of the Subalpine Basin (Ardèche, France) in Tucker et al. Carbonate platforms, facies, sequences and evolution Spec Publs int. Ass. Sediment. 9, 109-144. [9] Beerling, (2002) CO2 and the end-Triassic mass extinction. Nature 415, 386-387 [10] Retallack (2001) A 300 million-year record of atmospheric carbon dioxide from fossil plant cuticles. Nature; 411, 287-290. [11] Hautmann, (2004) Effect of end-triassic CO2 maximum on carbonate sedimentation and marine mass extinction. Facies, 50: 257-251

Micropalaontological and ichnological analysis of Triassic/Jurassic boundary cections of SW Britain MACDONALD, ELISABETH C.A.C. Department of Earth Sciences, University of Birmingham, Edgbaston, B15 2TT. [email protected]

At present, the micropalaeontology of the Triassic/Jurassic Boundary interval of SW Britain is poorly understood. This is somewhat surprising given the number of comparatively complete and fossiliferous sections crossing the boundary, and the historical importance of these sections. Classic T/J Boundary sections include St. Audrie’s Bay, Somerset; Pinhay Bay, Dorset and Lavernock Point, S Wales, all of which have been subject to extensive study of the macrofauna and lithostratigraphy. However, little work has been done to integrate microfossil, ichnological and sedimentological data in order to enhance understanding of the boundary interval and the mass extinction event at the close of the Triassic.

The distribution of microfossils (primarily Foraminifera and Ostracoda), together with ichnological and lithological data indicate fluctuations in palaeoecological conditions over the boundary interval. An abundance of taxa indicative of anaerobic conditions, together with a general lack of trace fossils throughout the Penarth Group, suggest low oxygen levels, whilst the presence of echinoid spines indicate that normal marine salinity conditions were prevalent. Microfossil distribution within the lower Blue Lias Group depict an overall trend of increasing oxygen levels, becoming open marine by the top of the Planorbis Subzone. Through the lower Blue Lias Group oxygen levels appear to fluctuating continuously, whilst generally increasing, although salinities remain relatively 19

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constant throughout. These results are consistent between sites in SW Britain indicating regional rather than local controls on ecological conditions. In recent discussions, a number of authors have presented different interpretations for the placement of the base of the Jurassic within the established lithostratigraphy. Traditionally, the first appearance datum of the ammonite Psiloceras planorbis which occurs in the lower beds of the Blue Lias Group, has been used at the boundary marker (for example, Cope et al., 1980). However, recent publications, have suggested this event may be diachronous in Britain, and

relates to an ecological rather than evolutionary control. Importantly, the preliminary micropalaontological data presented here appear to demonstrate that the foraminifera and ostracods show little, if any, response to such an ecological shift, implying a truly evolutionary earliest occurrence of Psiloceras planorbis. The lateral extent of these patterns is currently being tested from comparable sections in the English Midlands and Larne, N Ireland, in order to further correlate between sites in Britain.

Record of environmental changes in the Triassic/Jurassic boundary interval in the Zliechov Basin, Western Carpathians MICHALÍK, JOZEF 1, LINTNEROVÁ, OTÍLIA2, GAħDZICKI, ANDRZEJ3 & SOTÁK, JÁN4 1

Geological Institute, Slovak Academy of Science, Dúbravská 9, PO Box 106, 84005 Bratislava, Slovakia, [email protected] 2 Comenius University, Faculty od Science, Mlynská dolina, 842 15, Bratislava, Slovakia, [email protected] 3 Institute of Paleobiology, Polish Academy of Sciences, Twarda 51/55, 00-818 Warszawa, Poland, [email protected] 4 Geological Institute, Slovak Academy of Science, Severná 5, 974 01 Banská Bystrica, Slovakia, [email protected]

Depositional series of the Fatra and the Kopieniec Formations in the Zliechov Basin comprise record of several environmental crises that may contribute to the global Triassic / Jurassic (T/J) boundary events. The diversity of the benthic fauna decreases at the base of the "Transition Beds" the uppermost member of the Fatra Formation. This assemblage comprises many species which do not appear in younger strata. In the Cycle No 13, an isotope excursion corresponds to significant lithological changes in the sequence. The negative į13C excursion combined with a positive į18O peak is followed by thin layer with a peculiar lithological and mineral composition. It is composed of small

calcitized microsphaeres showing complicated transformation during diagenesis. The origin of this layer, traceable over tens of kilometers, is problematic (impact ejecta, volcanic glass, or altered aragonitic particles). A terrigenous event recorded as sandy beds in the uppermost part of the Fatra Formation indicates increased run-off. Sharp lithological boundary between the Fatra and the Kopieniec Fms is marked by sudden termination of carbonate sedimentation and followed by the Boundary Clay at the base of the Kopieniec Formation. Negative į13C anomaly recognized in this succession may correspond to isotope signature at the T/J boundary, which has been described from many sections in the world.

Radiolarian faunal change across the Triassic-Jurassic boundary in the CsĘvár section, Northern Hungary OZSVÁRT, PÉTER1 & ELIZABETH S. CARTER2 1

HAS-HNHM, Research Group for Paleontology, P.O. Box 137., H-1083., Budapest, Hungary; [email protected] Department of GeologyPortland State University, Portland, OR 97207-0751, USA; [email protected]

2

Radiolarians from CsĘvár were first reported by Kozur and Mostler [1], in a study on Hettangian saturnalids from Bavaria, Northern Calcareous Alps. Kozur [2] dated the upper part of the Várhegy Formation by the first appearance of Relanus hettangicus, considered the index for Hettangian in the Northern Calcareous Alps [1]. 20

During this study, more than 50 samples were processed by dissolving 0.7–1 kg rock in acetic acid. Following standard laboratory extraction techniques, the radiolarians were identified under a reflected light binocular microscope. The preservation is generally poor, the radiolarian tests are commonly recrystallized.

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Bed 4 contains abundant radiolarians, holothurians and sponge spicules. The radiolarians are mainly multicyrtid nassellarians belonging to the Globolaxtorum tozeri Zone (upper Rhaetian). The assemblage includes Canoptum triassicum, Canoptum spp., Globolaxtorum tozeri, Laxtorum capitaneum, L. perfectum, L. cf. porterheadense, L. spp., Pseudoeucyrtis sp., Syringocapsa rhaetica, and a few other species too poorly preserved to identify. In Bed 62 the spumellarians are more abundant than nassellarians. In the spumellarian fauna saturnalids are dominant (incl. Praehexasaturnalis, Paleosaturnalis, Pseudoheliodiscus, Stauracanthocircus, Pseudoacanthocircus, Spinoellipsella), whereas patulibracchids (incl. Paronaella) and pantanelliids (incl. Pantanellium) also occur. Besides, the spumellarian fauna also contains rare entactiniids (Charlottea and Tozerium) and other genera (Amuria, Plegmosphaera, Spongiomma, Praeorbiculiformella, Spongostaurus, Spongotrochus and Weverisphaera). The nassellarian fauna is comprised mainly of Relanus and Canoptum. Other genera (Bipedis, Laxtorum, and Syringocapsa) are only rare elements. The first Lower Jurassic zonation was developed on western North American distribution data [3]. Using this scheme, Bed 62 is assigned to the Hettangian Zone 05 (Canoptum merum Concurrent Range Zone, based on the presence of the species Relanus cf. reefensis. The lower boundary of this zone is defined by the first appearance of primary marker taxa Canoptum merum and its upper boundary by the last

appearance of Canoptum merum and Relanus reefensis. The correlation with the Tethyan areas is difficult, because here Canoptum merum has not been recorded in the lowermost Jurassic, however, it is said to occur in the upper Rhaetian of the Alps [1]. Alternatively, using the zonal scheme of Kozur & Mostler [1], the radiolarian assemblage of Bed 62 is assigned to the Relanus hettangicus Zone which is also regarded as Hettangian in age. This zone is confirmed here by coexistence of Relanus cf. reefensis, Relanus longus, and Pantanellium suessi. Further biostratigraphic constraints are inferred from the genera Bipedis and Tozerium. Carter et al. [4] identified their the age range as Hettangian to Sinemurian. Also diagnostic is the presence of Amuria impensa, Paleosaturnalis liassicus, Praehexasaturnalis poultoni and Paronaella botanyensis that co-occur in the lower part of the Protokatroma aquila Zone and the upper part of the Crucella hettangica Zone of Carter et al. [4]; this interval is correlated with the middle and upper Hettangian. An additional productive sample was collected from the south slope of Vár-hegy, above the measured section, approx. 40 m above Bed 62. Many species are represented by relatively wellpreserved, although fragile and recrystallized tests. The radiolarian assemblage of this sample is similar to Bed 62 and it is also assigned to the Hettangian Relanus hettangicus Zone. In conclusion, radiolarian biostratigraphic constraints place the TJB between Bed 4 (upper Rhaetian) and Bed 62 (Hettangian).

REFERENCES: [1] Kozur, H., 1993. First evidence of Liassic in the vicinity of CsĘvár (Hungary), and its paleogeographic and paleotectonic significance. Jahrbuch der Geologischen Bundesanstalt, 136(1): 89-98. [2] Kozur, H. and Mostler, H. 1990. Saturnaliacae Deflandre and some other stratigraphically important Radiolaria from the Hettangian of Lenggries/Isar (Bavaria/Northern Calcareous Alps). Geologisch und Paläntologische Mitteilungen 17:179-248. [3] Pessagno, E., Blome, C.D., Carter, E.S., Macleod, N., Whalen, P.A., and Yeh, K.-Y.1987. Preliminary radiolarian zonation for the Jurassic of North America, Studies of North American Jurassic Radiolaria, Part 2. Cushman Foundation of Foraminiferal Research, Special Publication, pp. 1–18. [4] Carter, E.S., Whalen, P.A. and Guex, J., 1998. Biochronology and paleontology of Lower Jurassic (Hettangian and Sinemurian) radiolarians, Queen Charlotte Islands, British Columbia. Bulletin - Geological Survey of Canada. Geological Survey of Canada, Ottawa, ON, Canada, 162 pp.

Palynology of the Triassic-Jurassic boundary of the Furkaska section (Tatra Mts., Slovakia) – first results RUCKWIED, KATRIN*1, GÖTZ, ANNETTE E.1 & MICHALÍK, JOZEF2 1

Institute of Geosciences, Martin-Luther-University Halle-Wittenberg, D-06099 Halle (Saale), Germany; E-mail: [email protected], [email protected] 2 Geological Institute, Slovak Academy of Science, Dúbravská 9, PO Box 106, SK-84005 Bratislava, Slovakia; E-mail: [email protected]

The studied Furkaska section near Oravice exposes a complete succession of the uppermost

Fatra Formation and lowermost Kopieniec Formation. The Upper Triassic Fatra Formation 21

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is characterised by bioclastic limestones and finegrained clastics overlain by dark claystones with intercalated sandstones (“Cardinia Sandstein”) of the Kopieniec Formation. Due to the lack of agediagnostic index fossils, the precise position of the Triassic/Jurassic boundary is not yet known. Based on geochemical data and microfacies analyses the boundary interval was placed near the transition of the two formations [1]. Here we present preliminary results of a palynological study, focused on palaeoenvironmental and stratigraphical aspects. Palynofacies of the entire succession is dominated by terrestrial components. Generally, the continental fraction shows a high amount of phytoclasts. The few marine organic particles indicate a very shallow marine depositional environment. The palynomorph assemblage of the Fatra Formation is characterised by numerous specimens of Ricciisporites tuberculatus. The marine fraction of the lower part of the section is dominated by the dinoflagellate cyst Rhaetogonyaulax rhaetica. The microflora of the Upper Fatra Formation is very similar to the

Ricciisporites tuberculatus Zone of the Polish zonation [2] and the Ricciisporites-Polypodiisporites Zone of the SE North Sea Basin [3], both indicating a Middle to Upper Rhaetian age. The palynomorph assemblage of the Kopieniec Formation is characterised by a significant increase of trilete laevigate spores, mainly Deltoidospora spp. and Concavisporites spp. The dinoflagellate cyst Dapcodinium priscum replaces Rhaetogonyaulax rhaetica in the marine fraction. These changes may be caused by a regression at the Triassic/Jurassic boundary [4]. However, the small amount of marine plankton did not allow this regressive trend to be detected. Ongoing studies focus on an integrated analysis of the organic facies and palynomorph assemblages of T/J boundary key sections in the W Carpathians. Such an analysis will give us a better insight into the floral changes within this time interval.

This study is part of a project on microfloral changes within T/J boundary key sections of Hungary and Slovakia, funded by the German National Science Foundation (Project GO 761/2-1).

REFERENCES: [1] Lintnerová, O. & Michalík, J. (2003) Sequence stratigraphy vs C and O isotopes across the T/J boundary beds in the Fatric, Tatra Mts. (central Western Carpathians). In: Michalík, J. (ed.) IGCP 458: Triassic/Jurassic boundary events. Third Field Workshop, Stará Lesná, Slovakia, 42-43. [2] Orlowska-Zwolinska, T. (1983) Palynostratigraphy of the upper part of Triassic epicontinental sediments in Poland. Prace Instytutu Geologicznego, Wydawnictwa Geologiczne 104, 1-89. [3] Lund, J.J. (1977) Rhaetic to Lower Liassic palynology of the onshore south-eastern North Sea Basin. Danmarks geologiske Undersøgelse, 2nd Series 109, 1-129. [4] Bergelijk, G., Kuerschner, W. & Krystyn, L. (2004) Palynology of the Triassic-Jurassic transition in the Northern Calcareous Alps (Austria). 32nd International Geological Congress 2004, Abstract Volume, Abstract 253-17.

Late Triassic events among reef ecosystems during the latest Triassic interval STANLEY, JR., G.D. Department of Geology, The University of Montana. Missoula, MT 59812 USA; [email protected]

Mass extinctions and faunal turnover characterize in the history of Triassic reefs. Reef development occurred throughout a vast shallow Tethys as well as in the ancient Pacific Ocean or Panthalassa. Following the mass extinctions of the Permian, the reef ecosystem did not take shape until the Middle Triassic (Anisian) and was characterized by the appearance of many new taxa. Among these new groups were scleractinian corals. Unrelated to Paleozoic ancestor, this new coral group, which appeared in the Anisian, likely developed from groups of soft-bodied anemonelike ancestors following episodes of calcification. These early Triassic corals however were not primary reef builders during the Anisian to Ladinian. Even in the early Late Triassic (Carnian) reef interval, corals took a backseat to chaetetid sponges, Tubiphytes, chambered (sphinctozoid) and non-chambered (inozoid) 22

sponges, bryozoans, numerous microproblematica and a diversity of calcareous algae. The Late Carnian to early Norian interval was characterized by mass extinctions and high biotic turnover at lower taxonomic levels—a process that reshaped the paleoecologic structure of reefs. At the end of a 13 million-year interval, 90% of older sphinctozoid sponges and coral taxa were extinct but were rapidly replaced by new general and species. This interval contains a reef biota of distinctly different composition from that of the previous one and it also was marked by the emergence of scleractinian corals as primary reef builders. It further was characterized by the diversification of chambered sponges (sphinctozoans) that evolved with corals as secondary reef builders. The rise to prominence of corals was most likely promoted by the evolution of a symbiotic association

2005 between scleractinian hosts and zooxanthellate algal symbionts. This relationship increased calcification rates and consequently also the reefbuilding potential of these corals. Reef ecosystems of the Late Triassic reached maximum diversity during the lengthy Norian interval, a time of carbonate expansion and relative sea level rise. During this interval, Norian platform carbonates expanded geographically across the shallow Tethys seaway, reaching thousands of meters in thickness and during that time, coral reefs were distributed at latitudes from 30q North to 35q South. Records of this reef interval are best preserved in carbonate sequences such as the spectacular examples from Norian reef complexes in the Northern Calcareous Alps. The Rhaetian interval reveals very little differences in taxonomic composition from that of the Norian but it was characterized by a notable reduction in diversity among genera and species. Some workers ascribe this diversity decline to the start of the endTriassic mass extinction. However, it appears more likely that the Rhaetian diversity decline was related to smaller scale, step-wise mass extinctions before the end of the Triassic. Resolution of details of this diversity decline are hampered by an inability to resolve sufficiently the dating and precise biostratigraphic correlations of intervals within the NorianRhaetian reef carbonate complexes of the Tethys. The end-Triassic was marked throughout the Tethys by a large-scale mass extinction. This extinction is recorded by large losses in taxonomic diversity without reciprocal replacement. It severely affected most of the reef organisms and in the Alpine reefs of the Tethys and appears to have been a relatively sudden event. A post-extinction decline, if not a reef eclipse, characterizes the Early Jurassic record. There also was a notable reduction in carbonate deposition throughout the Tethys. The rare reefs of the Early Jurassic interval (Hettangian to Pliensbachian) were mostly small-scale and patch like. Many of the Early Jurassic sequences are characterized by post-extinction survivors, such as among the stylophyllid corals. Full recovery among Early Jurassic corals took place in steps, including the gradual reduction of Triassic holdovers and the subsequent appearance of new taxa. The reef recovery was not complete until

ABSTRACTS Middle Jurassic time when a new reef ecosystem emerged. Some additional reef sequences were developed in more distant outposts in the ancient Pacific Ocean (Panthalassa). Many of these reefs developed upon or fringed oceanic volcanic island arcs. Some Upper Triassic sequences in North America were oceanic and contain excellent records of Tethyan-type reefs and carbonate platform deposits at locations very distant from those of the Tethys itself. These reefs in North America are among the collage of circum-Pacific accreted terranes found on both sides of Panthalassa but the stratigraphic records from North American accreted terranes are poor and largely incomplete, relative to those of the Tethys. The North American craton reveals a paucity of reef development and available data from parauthochthonous cratonal terranes of North and South America, indicate only smallscale patch reef ecosystems. Rare Carnian patch reefs are known from the craton of North America in B.C. Canada but poor preserved, precluding accurate comparisons. The best Upper Triassic records from North American terranes come from reef-rimmed volcanic island-arc settings. These ecosystems are paleoecologically similar to Tethyan examples and in addition, contain from 50-70 percent of species that are identical with counterparts from the Tethys. Distinctly Tethyan in the composition of the biota and also in the development of typical reef microfacies, a number of terrane examples are reported from western North America such as in the Yukon (Stikinia), B.C. Canada (Quesnellia), and the Oregon Wallowa terrane in the United States. These examples existed at paleolatitudes comparable to counterparts in the Tethys but subsequently were tectonically displaced to higher latitudes. Permian Lazarus taxa in Norian and Early Jurassic terrane reefs of North America contain Carnian holdovers and lend support to the idea that Panthalassan volcanic islands of the ancient Pacific functioned as refuges for the preferential survival of taxa during biotic crises that more severely affected the distant Tethys. A detailed stratigraphic study and dating of carbonate sequences in some of the key Cordilleran terranes is underway in order to test this idea more fully.

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Paleoautecology of Heterastridium: a globally distributed hydrozoan from upper Triassic terranes of the North American Cordillera STANLEY, JR., G. D. *1, MACKAY, M. L. 2 & SMITH, P. L. 3 1

Department of Geology, The University of Montana. Missoula, MT 59812 USA; [email protected] Department of Earth and Ocean Sciences, The University of British Columbia, Vancouver, BC V6T 1Z4 Canada; [email protected] 3 Department of Earth and Ocean Sciences, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada; [email protected] 2

Heterastridium conglobatum Reuss is a spherical, ellipsoidal or discoidal Upper Triassic colonial fossil with concentric growth bands. It displaces a wide range of morphological variation and smooth to finely pustulated surfaces characterized by abundant astrorhizae-like openings. It ranges in diameter from only a few centimeters to over 35 cm. Heterastridium is found globally distributed in Upper Triassic marine rocks, especially from those of the Tethys and the largest examples have been discovered in Iran. We have plotted the American Cordillera occurrences of this widespread taxon in both the North American craton and from accreted terranes. It occurs frequently in deep-water, radiolarian-rich, dark spicular calcareous mudstone, dark limestone and shale but also is found in a wide range of shallow-water deposits including reefs. It was characteristic of tropical to subtropical, shallow and deeper water settings. In the American Cordillera it frequently co-occurs with the flat clam Monotis in the Cordilleranus ammonoid zone of the Norian stage. Heterastridium evolved and went extinct within only a few biostratigraphic zones of the Late Triassic and it died out before the end of the Triassic. It appears to display a tendency for gradual size increase through the extent of its stratigraphic distribution, making it a potentially useful fossil for biostratigraphic zonation. The stratigraphic range, in accord with data from Timor and elsewhere, suggests small diameters (2-3 cm) in the Middle Norian (Alaunian 3/II) with larger diameters coming from younger strata (Leo Krystyn, personal communication). In Cordilleran terranes it ranges from upper Columbianus III to the Amoenum Zone (Serrulata to Mosheri conodont Zones). Based on comparisons with some living milleporids, a polymorphic hydrozoan afffinity for this extinct colonial fossil seems most reasonable. The interpretation of the autecology and functional morphology of Heterastridium is somewhat problematical. As an extinct taxon, it suffers from lack of homologous or analogous functional comparisons with living counterparts. By analogy with milleporids, it interpreted as a micropredatorial plankton feeder. This seems in accord with the coenosteum and the spacing and number of specialized zooids or individuals found in the colony. One hypothesis on its life style was that of a benthic colony, settling on and living on or near the substrate surface, hydrologically at or above normal wave base where it was constantly rolled about by wave action. Thus it is regarded as a benthic "rolling stone", similar to some living scleractinian corals. Another idea is that the spherical colonies floated at or near the ocean surface waters. A planktonic mode of life is favored due to the frequent occurrence of this taxon (from accreted terranes of North America) within dysaerobic and low-energetic, deep-water deposits and also by the large volume of pore space within the coenosteum. The original skeletal structure of the coenosteum was composed of aragonite organized into a fine lattice of pore spaces, likely filled with gas and/or lipids. Living individuals inhabited only the surface of the colony. The interior was sealed off from the seawater, providing a trap for gas and also creating neutral or positive buoyancy. Additional support for a planktonic life mode comes from the deeper water occurrences and the broad spectrum of rock types in which it is found. Following death, it is postulated that the rounded to discoid coenostea were capable of transportation for great distances by surface winds and currents before becoming water logged and sinking to the bottom of the sea. Global distribution and occurrences of this taxon in both the Tethys and most North American terranes demonstrates that this taxon was capable of long-distance dispersal. We propose that it was an important element of the surface plankton. The extinction of Heterastridium in the Amoenum zone occurred before the end of the Rhaetian stage. This accords well with the idea of step-wise pattern of biotic extinction before the end of the Triassic.

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Iridium enrichment at the Triassic-Jurassic boundary, Blomidon Formation, Fundy Basin, Canada TANNER, LAWRENCE H. *1 & KYTE, FRANK T.2 1

Dept. of Biological Sciences, Le Moyne College, Syracuse, NY 13204 USA, Email: [email protected] Center for Astrobiology, Institute of Geophysics and Planetary Physics, University of California, Los Angeles, CA 90095-1567 USA, Email: [email protected]

2

In the Fundy basin, Nova Scotia, a palynological transition interpreted as the Triassic-Jurassic boundary occurs in strata of the uppermost Blomidon Formation [1]. At Partridge Island, near the town of Parrsboro, the transition occurs between 30 and 40 cm below the North Mountain Basalt. We sampled the uppermost 1.0 m of the Blomidon Formation in 5 cm increments. One sample split was analyzed by neutron activation analysis (NAA) for concentrations of Ir and other selected elements (Sc, Cr, Fe, Co, Ni, Zn, Cs, Ce, Eu, Hf, Ta, and Th). A separate sample split was analyzed by nickel-sulfide fusion assay technique with ICPMS measurement (MS-NFA) to determine the concentrations of five platinum group elements (Ir, Pt, Pd, Rh, Ru) plus Au. Major element analyses (Al, Ca, Fe, K, Mg, Mn, Na, P, Ti, and Si as oxides) were conducted by X-ray fluorescence (XRF) of a third sample split. Results from MS-NFA and NAA exhibit good agreement in displaying a pattern of Ir enrichment at multiple horizons within the section; both methods identify the peak Ir concentration (309 pg/g) in the sample 30 cm below the North Mountain Basalt, the horizon that encompasses the putative boundary. Secondary peaks of Ir enrichment are identified in samples 10 cm and 45 cm and 10 cm below the basalt. Among other elements analyzed by MS-NFA, Au displays the strongest correlation with Ir. Concentrations of Pt also correlate with Ir, but not as strongly as for Au. Pd appears to correlate weakly with Ir, but not at a statistically

significant level. Concentrations of Rh and Ru were below the detection limits in most samples. Notably, the peak concentrations of Pd, Pt and Ru occur in the 5 cm interval immediately below the basalt. Among transition group elements analyzed by NAA, Zn, Co, Cr, and Fe appear to correlate weakly with Ir concentration, with Zn correlating most strongly. None of these correlations are statistically significant at the 95% confidence level. All other transition element and REE abundances display a lack of correlation with Ir concentration. Similarly, there is no apparent correlation between major element abundances, as determined by XRF, and Ir. The magnitude of the Ir enrichment we measure is similar to that observed by Olsen et al. [2-3] at the interpreted palynological boundary in the Newark basin. We note that the multiple enrichment intervals at Partridge Island occur in mudstones that are gray to laminated, but not in the red mudstones. Consequently, we consider the possibility that Ir enrichment at multiple levels in the gray mudstones is associated with diagenetic remobilization and redox boundary conditions. The ratios of Pd, Pt and Au to Ir exceed ratios for ordinary chondrites, typically by an order of magnitude for Au and Pd, and more closely resemble ratios characteristic of basalts or hydrothermal fluids. At this time, we consider both extraterrestrial and mantle-derived sources for the elevated iridium levels at the system boundary as viable hypotheses.

REFERENCES: [1] S.J. Fowell, A. Traverse (1995) Palynology and age of the upper Blomidon Formation, Fundy basin, Nova Scotia. Rev. Palaeobot. Palynol. 86, 211-233. [2] P.E. Olsen, D.V. Kent, H.D. Sues, C. Koeberl, H. Huber, A., Montanari, E.C. Rainforth, S.J. Powell, M.J. Szajna, B.W. Hartline (2002) Ascent of dinosaurs linked to an iridium anomaly at the Triassic-Jurassic boundary. Science 296, 1305-1307. [3] P.E. Olsen, C. Koeberl, H. Huber, A. Montanari, S.J. Fowell, M. Et-Touhani, D.V. Kent (2002) The continental TriassicJurassic boundary in central Pangea: recent progress and preliminary report of an Ir anomaly. Geol. Soc. Amer. Spec. Pap. 356, 505-522.

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Analyzing brachiopod distribution patterns before and after the Triassic-Jurassic mass extinction in the Northern Calcareous Alps (Austria) TOMAŠOVÝCH, ADAM *1 & SIBLÍK, MILOŠ 2 1

Institut für Paläontologie, Würzburg University, Pleicherwall 1, 97070 Würzburg, Germany, [email protected] 2 Institute of Geology, Academy of Sciences of the Czech Republic, Rozvojová 135, 165 00 Praha 6, Czech Republic, [email protected]

Although brachiopods were an important component of the Late Triassic and Early Jurassic benthic communities, an effect of extensive environmental disturbance on their ecology and evolution at the end of Triassic is poorly understood. Our study of pre- and postextinction brachiopod communities quantitatively demonstrates that distribution patterns and community-level abundance of brachiopods were substantially affected by the end-Triassic mass extinction event. Pre-extinction brachiopod communities. In the Kössen Basin (Northern Calcareous Alps), five brachiopod community types compositionally replace each other from the Early up to the Late Rhaetian. They are dominated by the dielasmatoids Rhaetina gregaria and R. pyriformis, the spondylospiroid Zugmayerella, rhynchonellids and the athyridoid Oxycolpella. As is shown by data from adjacent geographic regions (West Carpathians), Early Rhaetian communities migrate or track their habitats beyond the Kössen Basin and persist to top of the Rhaetian. This means that the disappearance of the Early Rhaetian brachiopods in the Kössen Basin reflects habitat tracking or local extinction events. Post-extinction brachiopod communities. Several brachiopod communities appear in upper Lower and Middle Hettangian deposits at the base of the Kendlbach Formation, above a several meters thick siliciclastic-rich bedset without brachiopods. The communities are dominated by the terebratuloid Lobothyris inhabiting calcareous sand habitats above NSWB, by rhynchonellids occupying siliciclastic-rich habitats below NSWB, or by rhynchonellids, zeillerioids and spiriferinoids in habitats with

reduced sedimentation rate below MSWB. This indicates their rapid recovery in terms of differential habitat preferences and compositional heterogeneity. Compositionally, these Hettangian communities have equivalent counterparts in later Jurassic stages. Change in community structure after the end-Triassic event. Non-metric multidimensional scaling and analysis of similarities indicate that superfamily turnover at T-J boundary resulted in differential composition of Rhaetian and Hettangian communities (R=0.5, p