CEPHALOPODCOQUINA BEDS IN THE WETTERSTEIN LIMESTONE (ANISIAN, HÖLLENGEBIRGE, SALZKAMMERGUT, AUSTRIA). Magyar 1223 4 Természettudományi Múzeum A. Vörös ; O. Piros ; T. Budai ; J. Haas ; H. Lobitzer 1Hungarian Natural History Museum, Department of Geology and Paleontology, HAS-HNHM Research Group for Paleontology, H-1083 Budapest, Ludovika tér 2; [email protected] 2Geological Institute of Hungary H-1143 Budapest, Stefánia út 14.# 3 HAS-ELTE Research Group for Geology H-1117 Budapest, Pázmány sétány 1/c.# 4 A-4820 Bad Ischl, Lindaustrasse 3, Ausztria

After Frisch & Gawlick 2003 Geology and geography Locality, collection Itwas very difficult to extract the fossils from the well-cemented limestone: after several hours of hammering, our team collected In the Middle Triassic large Wetterstein-type platforms developed only about sixty specimens of cephalopods. Despite the paucity on the passive margins of the western Neotethys Ocean. On the of fossils and the poor preservation the fauna is rather diverse platforms thick platform carbonates, i.e. cyclic peritidal–lagoonal and contains the following species:Mojsisovicsteuthis ? sp., sequences and marginal reef facies were formed. The Höllen- Ptychitessp., Flexoptychites cf. flexuosus , Megaphyllites ? sp., gebirge plateau in the northen part of the Northern Calcareous Proarcestessp., Norites dieneri, Hungarites sp., Parakellnerites sp. Alps is predominantly built up by an up to 500 m thick sequence of the Wetterstein Limestone. On the Feuerkogel the studied beds of the Wetterstein Limestone are made up predominantly of 2-5 mm-sized fragments of dasycladacean algae. Near Ebensee, on the Feuerkogel plateau, cephalopod bearing coquina interbeds consisting predominantly of orthocone cephalopods were found within the dasycladacean inner platform lagoon facies.

Lithology

Mass accumulation of fragments of Dasycladaceae algae Orthocone cephalopods

Depositional model Microfacies characteristics of the cephalopod-bearing beds do not differ significantly from those of the typical development of the Wetterstein Limestone, AfterHeinrich & Zankl (1986), implying similar depositional and diagenetic conditions. It means that a significant facies change i.e. relative sea-level rise modified could hardly be responsible for the peculiar cephalopod accumulation. Storm accumulation appears to be a more realistic interpretation. Subsequent to the storm event the cephalopod shells were encrusted by microbial coating which may have contributed to the preservation of the remnants. Similar interpretation was given for the occurrence of cephalopods in channels and in teepee structures in the cyclic lagoonal succession of the Latemar platform of the Dolomites.

tidal flat karst lagoon

backreef

reef flat

forereef REEF COMPLEX coral colonies spongiomorphs reef Tubiphytes nodules foreslope WETTERSTEIN TYPE PLATFORM LIMESTONE turbidite calcareous sponges basin vadose pisoidic crusts stromatolite intraclasts knoll reefs dasycladacea algae peritidal breccias marls grapestone

Sedimentological features Dasycladaceae flora Stratigraphical position The dominant elements of the algae flora are Teutloporella Characteristic microfacies herculea and Diplopora annulata annulata, so the age of the of the platform lagoon Characteristic microfacies of the cephalopod coquina complex isLate A nisian to Early Ladinian. The stratigraphical range ammonoid generaHungarites and Parakellnerites is confined to the Late Anisian Reitzi Zone.Norites dieneri occurred exclusively in the Avisianum Subzone. Consequently, the age of C the coquina beds can be restricted to the uppermost, Avisianum Subzone of the Reitzi Zone.

Ammonoidea fauna

Dasycladacean grainstone (with Diplopora Microbial particles (pseudo-oncoids) with Microbial particles and a fragment of calcified annulata annulata). The interparticle pores are irregular spar-filled pores. The particles are cyanobacteria (C). The particles are enveloped filled partly by peloidal micrite, partly by sparry enveloped by fibrous calcite cement, the larger by fibrous calcite cement, the larger pores are calcite pores are filled by drusy cement filled by drusy cement

1a-c:Norites dieneri Arthaber, 1903 2:Parakellnerites sp. 3:Parakellnerites sp. Dasycladacean wackestone (with Diplopora Fragments of ammonites in peloidal Microbial particles (pseudo-oncoids). In the 12–.Diplopora annulata annulata 4:Hungarites sp. annulata annulata). Clotted peloidal microspar microsparite matrix. The solution pores are central part of the picture a small gastropod is 3. Teutloporella peniculiformis 5:Megaphyllites ? sp. occurs among the coarse-grained bioclasts filled by sparry calcite coated by peloidal microsparite of microbial 4. Teutloporella herculea 6:Flexoptychites cf. flexuosus (Mojsisovics, 1882) origin