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(Oxfordian) Bentonite Deposits in the Paris Basin and the Subalpine Basin, France
Sedimentology (2003) 50, 1035–1060 doi: 10.1046/j.1365-3091.2003.00592.x Characterization and correlation of Upper Jurassic (Oxfordian) bentonite deposits in the Paris Basin and the Subalpine Basin, France PIERRE PELLENARD*, JEAN-FRANCOIS DECONINCK*, WARREN D. HUFF , JACQUES THIERRYà, DIDIER MARCHANDà, DOMINIQUE FORTWENGLER§ and ALAIN TROUILLER– *Morphodynamique continentale et coˆtie`re, UMR 6143 CNRS, University of Rouen, Department of Earth Sciences, 76821 Mont St Aignan Cedex, France (E-mail: [email protected]) University of Cincinnati, Department of Geology, PO Box 210013, Cincinnati, OH 45221-00, USA àBioge´osciences-Dijon, UMR 5561CNRS, Department of Earth Sciences, University of Burgundy, 6 bd Gabriel, 21000 Dijon, France §Le Clos des Vignes, Quartier Perry, 26160 La Be´gude de Mazenc, France –ANDRA, Parc de la Croix Blanche, 1–7 rue Jean Monnet, 92298 Chaˆtenay-Malabry, France ABSTRACT Explosive volcanic activity is recorded in the Upper Jurassic of the Paris Basin and the Subalpine Basin of France by the identification of five bentonite horizons. These layers occur in Lower Oxfordian (cordatum ammonite zone) to Middle Oxfordian (plicatilis zone) clays and silty clays deposited in outer platform environments. In the Paris Basin, a thick bentonite (10–15 cm), identified in boreholes and in outcrop, is dominated by dioctahedral smectite (95%) with trace amounts of kaolinite, illite and chlorite. In contrast, five bentonites identified in the Subalpine Basin, where burial diagenesis and fluid circulation were more important, are composed of a mixture of kaolinite and regular or random illite/smectite mixed-layer clays in variable proportions, indicating a K-bentonite. In the Subalpine Basin, a 2–15 cm thick bentonite underlain by a layer affected by sulphate–carbonate mineralization can be correlated over 2000 km2. -
Restudy of a Phylloceratid Ammonite from Peikang, Taiwan
PETROLEUM GEOLOGY OF TAIWAN NO. 16, P. 51-57, 1 PL., DEC. 1979 Restudy of a Phylloceratid Ammonite from Peikang, Taiwan TATSURO MATSUMOTO Kyushu University, Fukuoka, Japan ABSTRACT This is a result of my restudy on a phylloceratid ammonite which was previously obtained as one of the samples from the Well PK-2 drilled in western Taiwan by the Chinese Petroleum Corporation and described by Lin (1961). The ammonite is closely allied to but not quite identical with Holcophylloceras caucasicum (Sayn), from the Aptian of the Caucasus. Taking all the available data into consideration, I propose to call this ammonite Holcophylloceras caucasicum taiwanum Lin et Huang. This concept of geographical sub species is compatible with the conclusions of age correlation by Matsumoto et al. (1965) andT. C. Huang (1978). INTRODUCTION The Cretaceous ammonites and other molluscan fossils were described by Matsumoto et al.. (1965) on some samples from the two wells near Peikang, PK-2 and PK-3, drilled into the coastal plain of western Taiwan by the Chinese Petroleum Corporation. On that occasion a phylloceratid ammonite described by Lin (1961) was not included in the samples on loan. Fortunately I was invited to visit the Paleontological Laboratory of the Chinese Petroleum Corporation at Miaoli in April 1979, when Dr. Weng-Rong Chi kindly showed and let me study that specimen. This paper is to report the result of my restudy. PALEONTOLOGICAL DESCRIPTION Subclass Ammonoidea Order Phylloceratida Family Phylloceratidae Zittel, 1894 Genus Holcophylloceras Spath, 1927 Type-species.-Phylloceras mediterraheum Neumayr, 1871, by original designation. Generic diagnosis. See Arkell et al, 1957, p. -
Note on the Ammonite — Bearing Beds in the Various Localities of Turkey - Part One: Ankara Region
NOTE ON THE AMMONITE — BEARING BEDS IN THE VARIOUS LOCALITIES OF TURKEY - PART ONE: ANKARA REGION Mükerrem TÜRKÜNAL Mineral Research and Exploration Institute of Turkey INTRODUCTION While working on «The Mono- graphic Revision of the Ammonites Fa- una of Turkey» (to be published later), the author has prepared a note on the Ammonite-bearing beds of Turkey. In this note are assembled the data of the available literature on this subject with the listing of fossil names as given by the authors; the synonyms are given here only for a few well-known species. In the Monography, each of these fos- sils will be fully discussed and all the synonyms of the fossils will be given. In the present note, we are beginning with the beds of the Ankara region. The other localities will be the subject of the following notes. LOCALITY : ANKARA In this district, there are several beds known from the early works. The most important ones will be listed below. A - Balkuyumcu. — In 1887, Tchihatcheff (10) studied first this Jurassic outcrop and found concave-fractured limestone. This limestone contains : A. tortisulcatus (= Sowerbyceras tortisulcatum D'Orb.) A. ardennensis (= Peltoceratoides ardennensis D'Orb.) A. plicatilis (= Perisphenctes plicatilis Sow.) A. tatricus (= Phyllocefas tatricum (Pusch) ?) Age. — Oxfordian. 68 Mükerrem TÜRKÜNAL B - Kesiktaş. — Pompeckj (7), in 1897, made a detailed study of the Juras- sic of Ankara. In his book, he mentioned these fossils : Arietites cf. rotator Reynes A. cf. latesulcatus Quens. Aegoceras sp. aff. brevispinae Sow. Phylloceras alontinum frondosum Reynes Ph. hebertinum Reynes His fossil locality must be wrong. Because, according to several authors, no Jurassic series were encountered in the given locality. -
Jurassic Transgressions and Regressions in the Caucasus (Northern Neotethys Ocean) and Their Influences on the Marine Biodiversity
Palaeogeography, Palaeoclimatology, Palaeoecology 251 (2007) 422–436 www.elsevier.com/locate/palaeo Jurassic transgressions and regressions in the Caucasus (northern Neotethys Ocean) and their influences on the marine biodiversity Dmitry A. Ruban P.O. Box 7333, Rostov-na-Donu, 344056, Russia Received 17 May 2006; received in revised form 26 February 2007; accepted 24 April 2007 Abstract In the Jurassic, the Caucasus, presently located in the southwest of Russia, Georgia, Armenia and Azerbaijan, was located on the northern active margin of the Neotethys Ocean. Facies interpretation in all 62 areas, distinguished by differences in facies, allows to semi-quantitatively evaluate Jurassic regional transgressions and regressions for this region. Major transgressive regressive cycles took place in the Hettangian–Aalenian, Bajocian–Bathonian and Callovian–Tithonian. Each transgression was more extensive than the previous. The same cycles are established in the Greater Caucasus Basin. Deep-marine environments were common in the Pliensbachian, late Aalenian and late Bathonian, whereas they were very restricted in the Late Jurassic. The Jurassic transgressions and regressions in the Caucasus coincided with the proposed global eustatic changes. However, some differences were caused by the regional tectonic activity. Although transgressions and regressions cause some changes in marine biodiversity, it seems that only ammonites might have been directly influenced by them. Diversity of bivalves, brachiopods and belemnites was driven by other factors. However, global changes in marine biodiversity were more closely related to the eustatic fluctuations than it was documented on a regional scale. © 2007 Elsevier B.V. All rights reserved. Keywords: Transgression; Regression; Eustasy; Biodiversity; Jurassic; Caucasus 1. Introduction Wignall, 1999; O'Dogherty et al., 2000; Sandoval et al., 2001a,b; Smith, 2001; Sarti, 2003; Ruban, 2004; Aberhan Global sea level fluctuated strongly during the Juras- et al., 2005; Ruban and Tyszka, 2005; Ruban, 2006a). -
The Transversarium-Bifurcatus Zone Boundary at Rocha (Peral Area, East-Centralalgarve, Portugal)
The Transversarium-Bifurcatus Zone boundary at Rocha (Peral area, East-CentralAlgarve, Portugal) B.MARQUES * F. OLORIZ ** F. J. RODRIGUEZ-TOVAR ** P. S. CAETANO * * - Centro Estratigrafia e Paleobiologia da UNL, Faculdade de Ciencias e Tecnologia, Quinta da Torre, P-2825 Monte de Caparica, Portugal ** - Dpto. Estr. Paleont., Fac. Ciencias, Univ. Granada and Inst. And. Geol. Mediterranea (LA.G.M.) 18002 Granada, Spain pp. 109-125 Ciencias da Terra (UNL) Lisboa NQll 1992 3 figs., 2 pI. zones Bifurcatus/Bimammatum a ete reconnue une autre discontinuite, correspondanta celledu type II quisepareles RESUMO cycles 4.3-4.4 de HAQ et al. (1987); cette discontinuite avait deja ete individualisee sur la marge sud de I'Iberie. Palavras-chave: Amonites - Macroinvertebrados Dans I' intervalle entre la partie superieure de la zone bentonicas - Biostratigrafia - Ecostratigrafia a Transversarium et la partie inferieure de la zone a Descontinuidades-s--Jurdssico superior-Oxfordiano-:- Bimammatum,l'analysedel'evolutionecostratigraphique, Algarve- Sui de Portugal. faite a partir des spectres de la faune, a montre que dans I'ensemble des cephalopodes, les ammonites sont les Este trabalho representa 0 primeiro estudo organismesles plus tolerantsau stressecologique,provoque, pormenorizado do limite das Zonas de Transversarium soitparla diminution del'ecospace, soitpardes arrivees de Bifurcatus no Algarve. Este limite esta associado, na area materiel terrigene; dans ces conditions, la faune benthique do Peral, a uma descontinuidade estratigrafica cujo hiato diminue considerablernent. Dans l'ensemble de la faune afecta, parcialmente, as Zonas de Transversarium e de recoltce on signale la presence, relativement abondante et Bifurcatus. Uma outra descontinuidade foi reconhecida no diversifice, desDichotomoceras,auparavantpascommuns. limite das Zonas de Bifurcatus-Bimarnrnatum que, nesta area, coincide com a descontinuidade doTipo II que separa osciclos4.3-4.4 de HAQet al. -
Annual Meeting 2002
Newsletter 51 74 Newsletter 51 75 The Palaeontological Association 46th Annual Meeting 15th–18th December 2002 University of Cambridge ABSTRACTS Newsletter 51 76 ANNUAL MEETING ANNUAL MEETING Newsletter 51 77 Holocene reef structure and growth at Mavra Litharia, southern coast of Gulf of Corinth, Oral presentations Greece: a simple reef with a complex message Steve Kershaw and Li Guo Oral presentations will take place in the Physiology Lecture Theatre and, for the parallel sessions at 11:00–1:00, in the Tilley Lecture Theatre. Each presentation will run for a New perspectives in palaeoscolecidans maximum of 15 minutes, including questions. Those presentations marked with an asterisk Oliver Lehnert and Petr Kraft (*) are being considered for the President’s Award (best oral presentation by a member of the MONDAY 11:00—Non-marine Palaeontology A (parallel) Palaeontological Association under the age of thirty). Guts and Gizzard Stones, Unusual Preservation in Scottish Middle Devonian Fishes Timetable for oral presentations R.G. Davidson and N.H. Trewin *The use of ichnofossils as a tool for high-resolution palaeoenvironmental analysis in a MONDAY 9:00 lower Old Red Sandstone sequence (late Silurian Ringerike Group, Oslo Region, Norway) Neil Davies Affinity of the earliest bilaterian embryos The harvestman fossil record Xiping Dong and Philip Donoghue Jason A. Dunlop Calamari catastrophe A New Trigonotarbid Arachnid from the Early Devonian Windyfield Chert, Rhynie, Philip Wilby, John Hudson, Roy Clements and Neville Hollingworth Aberdeenshire, Scotland Tantalizing fragments of the earliest land plants Steve R. Fayers and Nigel H. Trewin Charles H. Wellman *Molecular preservation of upper Miocene fossil leaves from the Ardeche, France: Use of Morphometrics to Identify Character States implications for kerogen formation Norman MacLeod S. -
Redalyc.Upper Jurassic Ammonites and Bivalves from the Cucurpe
Revista Mexicana de Ciencias Geológicas ISSN: 1026-8774 [email protected] Universidad Nacional Autónoma de México México Villaseñor, Ana Bertha; González Léon, Carlos M.; Lawton, Timothy F.; Aberhan, Martin Upper Jurassic ammonites and bivalves from the Cucurpe Formation, Sonora (Mexico) Revista Mexicana de Ciencias Geológicas, vol. 22, núm. 1, 2005, pp. 65-87 Universidad Nacional Autónoma de México Querétaro, México Available in: http://www.redalyc.org/articulo.oa?id=57222107 How to cite Complete issue Scientific Information System More information about this article Network of Scientific Journals from Latin America, the Caribbean, Spain and Portugal Journal's homepage in redalyc.org Non-profit academic project, developed under the open access initiative Revista Mexicana de Ciencias Geológicas,Upper v. 22, Jurassic núm. 1, ammonites 2005, p. 65-87 and bivalves from Sonora 65 Upper Jurassic ammonites and bivalves from the Cucurpe Formation, Sonora (Mexico) Ana Bertha Villaseñor1,*, Carlos M. González-León2, Timothy F. Lawton3, and Martin Aberhan4 1 Departamento de Paleontología, Instituto de Geología, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510 México, D. F., Mexico. 2 Estación Regional del Noroeste, Instituto de Geología, Universidad Nacional Autónoma de México, 83000 Hermosillo, Sonora, Mexico. 3 Department of Geological Sciences, New Mexico State University, Las Cruces, NM 88003, USA. 4 Museum für Naturkunde, Zentralinstitut der Humboldt-Universität zu Berlin, Institut für Paläontologie, Invalidenstr. 43, D-10115 Berlin, Germany. * [email protected] ABSTRACT Four new molluscan assemblages from north-central Sonora indicate that the Cucurpe Formation ranges in age from late Oxfordian to early Tithonian. These assemblages extend the known paleogeographic range of Late Jurassic Tethyan fossil groups several hundred km to the northwest and improve correlation of Upper Jurassic strata in northern Mexico. -
The First Ar– Ar Date from Oxfordian Ammonite-Calibrated Volcanic
Geol. Mag.: page 1 of 7 c Cambridge University Press 2013 1 doi:10.1017/S0016756813000605 RAPID COMMUNICATION The first 40Ar–39Ar date from Oxfordian ammonite-calibrated volcanic layers (bentonites) as a tie-point for the Late Jurassic ∗ P. PELLENARD †, S. NOMADE‡, L. MARTIRE§, F. DE OLIVEIRA RAMALHO¶, F. MONNAࢱ & H. GUILLOU‡ ∗ Biogéosciences, CNRS-UMR 6282, Université de Bourgogne, F-21000 Dijon, France ‡LSCE-IPSL, CNRS-UMR 8212, CEA Orme, F-91191 Gif-sur-Yvette, France §Dipartimento di Scienze della Terra, University of Torino, via Valperga Caluso 35 10125 Torino, Italy ¶Statoil ASA, Grenseveien 21, 4313 Forus, Norway ࢱARTeHIS, CNRS-UMR 6298, Université de Bourgogne, F-21000 Dijon, France (Received 26 December 2012; accepted 1 July 2013) Abstract European domains (Cariou & Hantzpergue, 1997; Morton, 2006). However, provincialism in Boreal, sub-Boreal, sub- Eight volcanic ash layers, linked to large explosive events Mediterranean and Tethyan domains prevents unequivocal caused by subduction-related volcanism from the Vardar zonation correlation, especially for certain intervals, and Ocean back-arc, interbedded with marine limestones and hence introduces a temporal bias in the magnetostratigraphic cherts, have been identified in the Rosso Ammonitico Ver- model. Despite recent progress in reducing this bias (Ogg onese Formation (northeastern Italy). The thickest ash layer, et al. 2010; Przybylski et al. 2010; Gradstein et al. 2012), the attributed to the Gregoryceras transversarium ammonite scarcity of interbedded volcanic units in ammonite-bearing Biozone (Oxfordian Stage), yields a precise and reliable 40 39 ± marine successions hinders the accurate numerical calibra- Ar– Ar date of 156.1 0.89 Ma, which is in better tion of the Late Jurassic Time Scale, even with the progress agreement with GTS2004 boundaries than with the current made in the GTS2012, including improved numerical ages GTS2012. -
Taxonomy of Perisphinctid Ammonites of the Early Oxfordian (Late Jurassic) from Near Herznach, Canton Aargau, Switzerland
Palaeontographica Abt. A 251 Lfg. 1-4 1-37 Stuttgart, Dezember 1998 Taxonomy of perisphinctid ammonites of the Early Oxfordian (Late Jurassic) from near Herznach, Canton Aargau, Switzerland by REINHART A. GYGr'') With 14 plates, 25 figures and 22 tables in the text Zusammenfassung 1336 Ammoniten des fruhen Oxfordiums sind Schicht fur Schicht in einer FLichengrabung auf dem Brunnrain bei Uken gesammelt warden, einem Dorf in der Nahe des heute geschlossenen Eisenbergwerks Herznach. Weitere Ammoniten stammen aus versturzten Bliicken in den Stollen des Bergwerks Herznach. Die Perisphinctiden machen 42% der Ammonitenfauna aus. Ein betrachtlicher Teil von ihnen wird hier erstmals beschrieben. Eine neue Gattung unci eine neue Untergattung werden vorgeschlagen, welche wahrscheinlich ein dimorphes Paar bilden. 8 neue formelle unci zwei neue informelle Taxa der Artgruppe wurden erkannt. Die genauen Alter (Subchron) von fruher beschriebenen Arten werden hier erstmals angegeben. Schlusselwiirter: Ammoniten- Oxfordium- Jura- Schweiz. Summary 1336 ammonites of Early Oxfordian age have been collected bed by bed from a systematic excavation on the Brunnrain near Uken, a village close to the now closed iron mine of Herznach. Some additional ammonites came from fallen blocks in the Herznach mine. The perisphinctids are 42% of the ammonite fauna, a considerable number of them being new. One new genus and a new subgenus are proposed which are probably a dimorphic pair. 8 new formal and two new informal taxa at the species level are presented. The exact ages (subschron) of some previously described species can now be indicated. Key words: Ammonites - Oxfordian- Jurassic- Switzerland Contents 1. Introduction . 2 Sub genus Eichiniceras n. -
Barremian Rhyncholites (Lower Cretaceous Ammonoidea: Calcified Upper Jaws) from the Serre De Bleyton (Département Drôme, SE France)
©Naturhistorisches Museum Wien, download unter www.biologiezentrum.at Ann. Naturhist. Mus. Wien, Serie A 112 627-658 Wien, Juni 2010 Barremian rhyncholites (Lower Cretaceous Ammonoidea: calcified upper jaws) from the Serre de Bleyton (Département Drôme, SE France) By Wolfgang RIEGRAF1 & Gero MOOSLEITNER2 (With 2 figures, 2 plates and 1 table) Manuscript submitted on June 10th 2009, the revised manuscript on January 19th 2010 Abstract Seven calcified upper jaw tips of Rhynchoteuthis astieriana D’ORBIGNY and Palaeoteuthis infira (SHIMANSKY) from the Serre de Bleyton section (Dépt. Drôme, SE France) were redeposited from an outer shelf into an upper slope (upper bathyal) environment embedded in a highly fossiliferous Barremian bioclastic limestone. They represent a low diverse and poor preserved small Barremian pelagic rhyncholite fauna, also described from a few Tethyan and Alpine localities between Cuba, the Crimea, and the Caucasus. Rhynchoteuthis and Palaeoteuthis may most probably represent calcified tips of upper jaws of various taxa of Tethyan ammonites, e.g. of the Phylloceratina (Phyl- loceras, Sowerbyceras), Lytoceratina (Tetragonitidae), and/or some Ammonitina (Arnioceras, Eleganticeras, Hildoceras, Aconeceras). But due to their scarcity, poor preservation, and the allochthonous occurrence, the Serre de Bleyton rhynchoteuthids do not contribute further new knowledge to taxonomy, palaeoecology, stratigraphy or basinal history. Kurzfassung Sieben kalkige Oberkieferspitzen – Rhynchoteuthis astieriana D’ORBIGNY und Palaeoteuthis infira (SHIMANSKY) aus einem Profil der Serre de Bleyton (Dépt. Drôme, SE-Frankreich) – gelangten vom Schelf durch Umlagerung in ein oberbathyales Milieu des oberen Kontinentalabhangs, in einen äußerst fossilreichen bioklastischen Kalkstein. Solche geringdiversen und mäßig erhaltenen pe- lagischen Rhyncholithenfaunen des Barremium sind auch von vereinzelten tethyalen und alpinen Fundorten zwischen Kuba, der Krim und dem Kaukasus beschrieben. -
Pdf) on July 4, 2021 [Editor: Bruno R.C
Carnets Geol. 21 (13) E-ISSN 1634-0744 DOI 10.2110/carnets.2021.2113 Kimmeridgian and early Tithonian cephalopods from the Kisújbánya Limestone Formation, Zengővárkony (Mecsek Mountains, southern Hungary), their faunal composition, palaeobiogeographic affinities, and taphonomic character László BUJTOR 1, 2 Richárd ALBRECHT 1, 3 Csaba FARKAS 1, 4 Bertalan MAKÓ 1, 5 Dávid MARÓTI 1, 6 Ákos MIKLÓSY 1, 7 Abstract: A new collection at Zengővárkony (Mecsek Mountains, Hungary) provided a rich and diverse but poorly preserved cephalopod-dominated fossil assemblage representing the Kimmeridgian and the lower Tithonian. The material came from mixed scree, soil, and amongst roots affected by weathering processes having been exposed to the elements for a long time. The nautiloid Pseudaganides stram- bergensis is the first record from the Mecsek Mountains. Due to the weathering, the ammonite fauna consists of mainly fragmentary and dissolved individuals that comprises 528 specimens belonging to 34 species and 30 genera out of which 20 species and 15 genera are reported for the first time from the Mecsek Mountains. The fauna includes specimens of known taxa. No new taxa are introduced. Based on the comparison with other faunas, this assemblage most closely resembles the fauna of the Venetian Alps (Italy). Additional faunal elements include aptychi ( Laevaptychus latus , Lamellaptychus murocostatus) , belemnites ( Hibolithes semisulcatus ), and an indetermined brachiopod. The first record of Spiraserpula spirolinites , an encrusting fossil polychaete preserved on the internal mould of a Tara- melliceras shell fragment indicates favourable bottom conditions for the epifauna. The presence of Aspidoceras caletanum , Gravesia aff. gigas , and Pseudowaagenia inerme indicates faunal connections with the Submediterranean Province of the Tethys, which is in line with the tectonic and palaeogeogra- phical position of the Mecsek Zone during the Late Jurassic. -
A Barremian Ammonoid Association from the Schneeberg Syncline
ZOBODAT - www.zobodat.at Zoologisch-Botanische Datenbank/Zoological-Botanical Database Digitale Literatur/Digital Literature Zeitschrift/Journal: Annalen des Naturhistorischen Museums in Wien Jahr/Year: 2004 Band/Volume: 106A Autor(en)/Author(s): Lukeneder Alexander Artikel/Article: A Barremian ammonoid association from the Schneeberg Syncline (Early Cretaceous, Northern Calcareous Alps, Upper Austria) 33-51 ©Naturhistorisches Museum Wien, download unter www.biologiezentrum.at Ann. Naturhist. Mus. Wien 106 A 33–51 Wien, November 2004 A Barremian ammonoid association from the Schneeberg Syncline (Early Cretaceous, Northern Calcareous Alps, Upper Austria) by Alexander LUKENEDER1 (With 10 text-figures and 2 plates) Manuscript submitted on 10 June 2003, the revised manuscript on 7 May 2004 Abstract An Early Barremian ammonoid fauna from the Lower Cretaceous Schrambach Formation of the Schnee- berg Syncline (Reichraming Nappe, Northern Calcareous Alps) yielded 8 genera, each represented by 1 or 2 species. The exclusively Mediterranean ammonoids are dominated by Barremites (54.2%) of the Ammonitina, followed by the Lytoceratina (22.9%), Phylloceratina (12.5%) and Karsteniceras (10.4%) from the Ancyloceratina. Key words: Ammonoids, Lower Cretaceous, Barremian, Schneeberg Syncline, Northern Calcareous Alps Zusammenfassung Eine Unter-Barremium Ammonoideen Fauna aus der unterkretazischen Schrambach Formation der Schnee- berg Mulde (Reichraming Decke, Nördliche Kalkalpen) erbrachte 8 Gattungen, von welchen jede durch 1 bis 2 Arten vertreten ist. Die ausschließlich mediterranen Ammonoideen werden von Barremites (54.2%) aus den Ammonitina dominiert, gefolgt von Lytoceratina (22.9%), den Phylloceratina (12.5%) und Karsteniceras (10.4%) aus den Ancyloceratina. Schlüsselworte: Ammonoideen, Unterkreide, Barremium, Schneeberg Mulde, Nördliche Kalkalpen 1. Introduction Lower Cretaceous pelagic sediments (Schrambach Formation) form a major element of the northernmost tectonic units of the Northern Calcareous Alps (e.g.