^-~> L JL-J Cenomanian-Coniacian Ammonoids of The
Total Page：16
File Type：pdf, Size：1020Kb
SDGG, Heft 65 - Litho- und Biostratigraphie der außeralpihen Kreide von Bayern ^TE0J1^> 11 ] ^-~> L_JL-J Cenomanian-Coniacian ammonoids of the DanubianCretaceous Group (Bavaria, southern Germany) I MARKUS WILMSEN ', CHISTOPHER J.JTöocT2, BiRGIF^TEBUHR^-ÄT ULRICH KAPLAN^, 1 Scnckenberg~Käturhistorischc SarnmTüngen Dresden/Museum für Mineralogie und Geologie. Königsbrücker Landstr. 159, D-Ol 109 Dresden, <markus.wilmsen!ä;senckenberg.de> - Scops Geological Services Ltd., 31 Periton Lane, Minehead, Somerset, TA24 8AQ, U.K., <chrisjwood(äibtopenworld. com> * Sagarder Weg 2, D-Ol 109 Dresden, <[email protected]> 4 Eichenallee 141, D-33332 Gütcrsloh.<[email protected]> Abstract . — This paper presents a compilation of the ammonoid records of the Danubian Cretaceouos Group, supplemented with new data on their taxonomy and biostratigraphy. The study is based on material of the Museum für Mineralogie und Geologie in Dresden, the Bayerische Staatssammlung für Paläontologie in Munich and the Juramuseum Eichstätt as well as a taxonomic re-evaluation of the ammonoids described and figured by DACQUE (1939). Unfortunately, the ammonoids of the Danubian Cretaceouos Group are generally rare and of low diversity. Furthermore, they arc often poorly preserved and, thus, several specimens have to be kept in open nomenclature. In total, twenty-four Ccnoma- nian, Turonian and Coniacian ammonoid taxa are recorded: Manielliceras inantelli (J. SOWERBY, 1814), Calycoceras {Calycoceras)naviculare (MANTELL, 1822), Metoicoceras geslinianum (D'ORBIONY, 1850), Euomphalocerus septemse- rialum (CKAGIN, 1893), Pseiidocalycoceras angolaense(SPÄTH, 1931),Ps. cf. harpax (SIOLICZKA, 1864), Romaniceras (Romaniceras) kallesi! (ZAZVORKA, 1958), Vascocerasdiartianum (D'ORBIGNY, 1850). Lewesicerasperamplum (MAN- TKU., 1822), he. manteM WRIGHT & WRIGHT, 1951, Collignonic eras'! woollgari1? (MANTELL, 1822), Subprionocyclus sp„ Su. neptuni'! (GEIMTZ, 1849), Peroniceras (Peroniceras) westphaticum (STROMBECK, 1859). Ptacenticeras! sp., Worthoceras vermiculum (SHUMARD, I860), Hemiptyehoceras sp., He. cf. reesidei COBBAN & Scon, 1972, Scipono- ceras sp.. Sc. gracile? (SHUMARD, 1860), Sc. bohemicum? (FRITSCH, 1872), Bacuiites sp., Scaphites sp. and Scaphites kieslingwaldensis doylef! WRIGHT, 1978. Most taxa are illustrated, briefly described and placed within the new litho- and biostratigraphie framework of the Danubian Cretaceouos Group (see NIEBLHR el al. 2009; TROGLR et aL 2009). Keywords: Southern Germany. Bavaria, ammonoids, taxonomy, biostratigraphy. Upper Cretaceous, Cenomanian, Turonian, Coniacian Kurzfassung Diese Arbeit kombiniert das Auftreten von Ammonoideen der Danubischen Kreide-Gruppe mit neuen Daten bezüg lich ihrer Taxonomie und Biostratigraphie. Sie basiert auf Material aus dem Museum für Mineralogie und Geologie in Dresden, der Bayerischen Staatssammlung für Paläontologie in München und dem Juramuseum Eichstätt. Auch die von DACÜ-UL (1939) beschriebenen und abgebildeten, spater verloren gegangenen Ammonoideen wurden einer taxonomischen Neubetrachtung unterzogen. Ammonoideen sind in der Danubischen Kreide-Gruppe jedoch generell sehen und gering divers. Weiterhin sind sie oftmals schlecht erhalten, sodass eine nicht geringe Anzahl der Stücke in offener Nomenklatur verbleiben muss. Insgesamt wurden vierundzwanzig Ammonoideen-Taxa aus dem Cenomanium, TuronJum und Coniacium bestimmt: Mantetliceras mantelli (J. SOWERBY, 1814), Calycoceras {Calycoceras) navkulare (MANTELL, 1822), Metoicoceras gestinianum (D'ORBIGNY, 1850), Euomphalocerus septemseriatum (CRAGIN, 1893). Pseudoculycoceras angolaense (SPÄTH; 1931), Ps. cf. harpax (STOLICZKA, 1864), Romaniceras (Romaniceras) kullesi'! (ZAZVORKA, 1958), Vascoceras diartianum (D'ORBIGNY, 1850), Lewesiceras perumplum (MAN ILI.L, 1822),/.f. mantelli WRIGHT & WRIGHT, 1951, Coltignoniceras! woollgari? (MANTELL, 1822), Subprionocyelus sp.. Su, neptum! (GHMI/. 1849), Peroniceras (Peroniceras) westphaticum (STROMBLCK, 1859), Ptaeenticeras'! sp., Worthocems vermiculum (Sm - MARD. 1860), Hemiptyehoceras sp., He. cf. reesidei COBBAN & SCOTT, 1972, Sciponoceras sp.. Sc. gracile! (SHUVIAKD, 1860),Sc. bohemicum'!(FRITSCH, 1872), Bacidiles sp., Scaphites sp. und ScaphiteskieslingwaldensisdoyleP. WKIGIII, 1978. Die meisten Taxa wurden abgebildet, beschrieben und in die neue litho- und biostraiigraphische Gliederung der Danubischen Kreide-Gruppe (siehe NIKHI.HR et al. 2009; TRÖGER et al. 2009) integriert. Schlüsselworte: Süd-Deutschland, Bayern, Ammoniren, Taxonomie, Biostratigraphie, Überkreide, Cenomanium, Turonium, Coniacium 112 SDGG, Heft 65 - Litho- und Biostratigfaphie der außeralpinen Kreide von Bayern 11ntroduction 1.1 Geological setting Despite nearly 200 years of palaeontological and stra- During the Late Cretaceous transgressions, vast areas of tigraphic research on the Cretaceous strata that crop the northern Tethyan margin were flooded and became out north of the Alpine Molasse in northern Bavaria peri-continental shelf seas. In northern Bavaria (sou (formerly often termed "Regensburger Kreide", now thern Germany), this development is exemplified by the formalized within the Danubian Cretaceous Group; onlap of the Danubian Cretaceous Group (NIEBUHR et al. 2009; WILMSEN & NIEBUHR 2010). The constituent see NIEBUHR et al. 2009), their biostratigraphy is still somewhat crude. This is mainly due to the fact that formations of this group represent non-marine to neritic ammonoids, the classic index fossils, are relatively environments, comprising conglomerates, sands and rare and important collections such as those of TRUS- sandstones, clays, marls and marlstones, calcarenites, HEIM (1935) and DACQUE (1939) were for the most part siliceous opoka and limestones, with a total thickness lost during the World War II. Furthermore, the out of 300 to 500 m. Terrestrial deposits are known from crop conditions are very poor and the preservation of the Lower Cretaceous (Schutzfels Formation) and range the fauna is often poor. Consequently the records of from the Middle Turanian into the Coniacian (or Santo- ammonites from the Danubian Cretaceous Group are nian?, Hessenreuth Formation). Marine units start with sparse and scattered in the literature, and there have the Lower Cenomanian and persist into the Coniacian. been few taxonomic revisions. The complete succession documents a nearly symme trical transgressive/regressive cycle with a maximum The scope of the present paper is a compilation of flooding interval during the late Middle to early Late the available ammonoid records supplemented with Turanian (NIEBUHR et al. 2009). new data on taxonomy and biostratigraphy. For this purpose, collection material of the Museum für Mine From nine formations of the Danubian Cretaceous ralogie und Geologie in Dresden, the Bayerische Group which exclusively consist of marine sediments Staatssammlung für Paläontologie in Munich and the (see NIEBUHR et al. 2009), seven yielded ammonoids: Juramuseum Eichstätt has been examined. For lost The Regensburg Formation (lower Lower Cenomanian specimens such as most of the ammonoids described to Upper Cenomanian in the Regensburg-Kelheim by DACQUE (1939), a taxonomic re-evaluation based on area, Fig 1/1) is characterized by strong terrigenous the illustrations is provided where possible. input and glauconitic-bioclastic mixed sediments with a shallow-water fauna which accumulated mainly in the . 44|.. 45. ; IK 251 Oanubiau Cretaceous Group Cretaceous below molasse Fig. 1: Distribution of the Danubian Cretaceous Group in Bavaria, and key areas with different lithological development (according to NIEBUHR et al. 2009): (I) type region Regensburg-Kelheim, (II) proximal Bodenwöhrer Senke, (III) siliceous Wellheim Formation west of Ingol stadt, (IV) Cretaceous of the Franconian Alb northeast of Nürnberg, (V) terrestrial Hessenreuth Formation, (VI) Sandbach Formation west of Passau .in <fcr DOJUUI.. Passau. SDGG, Heft 65 - Litho- und Biostratigraphie der außeralpirien Kreide von Bayern 113 (I) Regensburg-Kelheim (VI) Ortenburg near Passaul •o nodules of siliceous limestone sandstone tilled burrows 0^r* TUM » • conglomerate <> 5 S hioturbation ammonite heteramorph ammonites ^) nautiloids •-s shells bioclasts /Sietoicocerasgeslinianum, Catycocerws (Ca.) navicular?, t Euomphatocerax *eptentseriarnm. Pseudocalyeoctrus angolacnse. jPs cf.harpax, Vascoceras diartianum, IVorihoceras vermicutum. j \ihjmiptychoceras sp., He. cf. reesidvi, Sciponoceras sp., Sc gracile'] "3 S '^Calycoceras naviculare CC 2 ^Acanthoceras rhulomagense ) Siantelticeras mantelli y?MT] (Sch u tzfels Fig. 2: Standard section of the Danubian Cretaceous Group in the Regensburg-Kelheim area (left, see Fig. 1/1) and the Orten burg area west of Passau (right, see Fig. 1/VI) with indication of ammonite horizons. 114 SDGG. Heft 65 - Litho- und Biostratigraphie der außeralpinen Kreide von Bayern northeastern parts of the basin, close to the emergent mannshofer Sandstein (= Jeding Formation). TRUSHIIM Variscan source areas (Fig. 1). The following ammo (1935), in his influential stratigraphic revision of the nite- and planktonic foraminifera-bearing uppermost Lower Cretaceous and Cenomanian of the Danubian Cenomanian-lower Lower Turonian silty marls of Cretaceous Group, listed some ammonites from the the Eibrunn Formation document a first maximum Regensburg and Eibrunn formations, however, without flooding interval. This formation is overlain by the figuring them. DACQUE (1939) presented a monogra spiculitic siltstones (Reinhausen