Austroalpine Liassic Ammonites from Vorarlberg (Austria, Northern Calcareous Alps)
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Beitr. Paläont., 28:9–99, Wien 2003 Austroalpine Liassic Ammonites from Vorarlberg (Austria, Northern Calcareous Alps) by Christian MEISTER*) & J. Georg FRIEBE**) MEISTER, C. & FRIEBE, J.G., 2003. Austroalpine Liassic Ammonites from Vorarlberg (Austria, Northern Calcareous Alps). — Beitr. Paläont., 28:9–99, Wien. Contents Zusammenfassung Abstract.......................................................................... 9 Die Ammoniten des Sinemurium und Pliensbachium der Zusammenfassung.......................................................... 9 Nördlichen Kalkalpen aus der historische Sammlung der 1. Introduction................................................................ 9 Vorarlberger Naturschau (Dornbirn) werden beschrie- 2. Regional setting ....................................................... 10 ben, abgebildet und biostratigraphisch verortet. Neuauf- 3. Systematic Paleontology.......................................... 21 sammlungen im Steinbruch Lorüns sowie im Steinernen Phylloceratoidea ZITTEL, 1884................................. 21 Meer (Lechquellengebiet) ergänzen die Studie. Lytoceratoidea NEUMAYR, 1875 ............................... 29 Psiloceratoidea HYATT, 1867 ................................... 29 Eoderoceratoidea SPATH, 1929 ................................ 39 1. Introduction Hildoceratoidea HYATT, 1867 .................................. 50 4. Biostratigraphical framework .................................. 54 This study is based mainly on the (historical) collections 4.1. Sinemurian........................................................ 54 of the Vorarlberger Naturschau (Dornbirn, Austria). 4.2. Pliensbachian.................................................... 55 Most of the specimens were collected by the founder of 5. Conclusion ............................................................... 55 the museum, Siegfried FUSSENEGGER, and determined in 6. Acknowledgements.................................................. 55 the late 20-ies to early 30-ies by Walter BIESE in Berlin 7. References................................................................ 55 (FRIEBE, 1999). BIESE visited Vorarlberg several times for Plates............................................................................ 66 field work. The preserved correspondance between him and FUSSENEGGER indicates that a manuscript containing both a description of the fossils and a documentation of the Abstract outcrops was nearly finished, when IESEB left Germany and emmigrated to Chile in 1934. Thus this paper was never The historical collection of the Sinemurian – Pliensbachian published. FUSSENEGGER, however - relying on BIESE to ammonites from the Vorarlberger Naturschau (Dornbirn) write the documentation - recorded only the name of the are herein described, illustrated and placed into their location and an approximate lithostratigraphic position. biostratigraphical framework. Additionally some new Additional material originates from the former collection investigations in Lorüns Quarry and in Steinernes Meer of the Vorarlberger Landesmuseum in Bregenz (FRIEBE, support this study. 2000) and from private donations by Joe VINCENZ and Antonio WEHINGER. Obviously most of these specimens were found in the scree. Thus no reliable documentation of the exact locations is available. Field studies in the Lorüns quarry and in the Lech- quellen area (Steinernes Meer) helped to establish a rough *) Dr. Christian MEISTER, Muséum dʻHistoire Naturelle de correlation between some of the fossils in the collection and Genève, Département de Géologie et Paléontologie, 1 the stratigraphic column. Moreover the comparison with well Rte de Malagnou, cp 6434, CH-1211 Genève 6, e-mail: horizonted material of several recent studies in the Austrian [email protected] Upper Austroalpine units (BLAU & MEISTER,1991; MEISTER & BÖHM, 1993; MEISTER et al., 1994; BÖHM et al., 1995; **) Dr. J. Georg FRIEBE, Vorarlberger Naturschau, DOMMERGUES et al, 1995) allow to precise the biostratigra- Marktstrasse 33, A-6850 Dornbirn, e-mail: Georg.Frie- phical position and to revise the taxonomy of the Vorarlberg [email protected] ammonites. 10 Beiträge zur Paläontologie, 28, Wien, 2003 MEISTER, C. & FRIEBE, J.G., Austroalpine Liassic Ammonites … 11 2. Regional Setting In the Northern Calcareous Alps of Vorarlberg two main nappes can be distinguished (figs. 1, 2). A more or less complete stratigraphic succession from the Late Permian / Early Triassic to the Cretaceous is preserved in the (upper) Lechtal nappe, which covers the Rhätikon, the Lechquellen and the Arlberg area. Gypsum beds whichin the Raibl Formation acted as a detatchment horizon for the (lower) Allgäu nappe, which thus contains only Upper Tri- assic to Cretaceous sediments. In Vorarlberg the latter can be found in the eastern Grosswalsertal and the Hochtan- nberg area (OBERHAUSER, 1998). These two nappes roughly correspond to a liassic facies diffentiation. Red nodular limestones of the Adnet Formation are characteristic for the Lechtal nappe, whereas the Allgäu nappe containes predominantly well bedded marl-limestone alternations of the Allgäu Formation (fig 3). Lechtal Nappe – Lorüns Lorüns Quarry (figs. 4-8) A complete profile from the Upper Triassic (Rhaetian) to the Upper Cretaceous (Cenomanian / Turonian) of the Lechtal Nappe is exposed in the Lorüns Quarry (cf. BERTLE Figure 1: Geological overview of Vorarlberg. et al., 1979; FURRER in OBERHAUSER, 1986). The success- sion starts with alternating limestones and marls, including typical Adnet Limestone by the absence of a pronounced coral carpets and Megalodon beds, of the Ramoz Member nodular fabric and a less red or even (greenish) grey (Kössen Formation) and the informal Zirmenkopf lime- colour. Its base shows some influence of the preceeding stone (partly corresponding to the “Oberrhätkalk” in earlier unit (crinoid microonkoid packstone; intermittent facies publications; FURRER, 1993). The succeeding alternation of between microfacies [= MF] 24: microonkoid packstone shales, marls and marly limestones represents the (infor- and MF 16: crinoidal packstone / wackestone [after BÖHM. mal) Schattwald beds. It is dated as early Hettangian. 1992]). The main part of the unit is dominated by MF Limestone sedimentation started again with the (informal) 5b: spiculitic microbioclastic wackestone. Additionally Lorüns oolite, a massive to poorly bedded oncoid / ooid spots of MF 9: spiculitic stromatactis wackestonne and packstone to grainstone (Text-Fig. 3). The original mic- layers enriched in crinoid debris (comparable to MF 10: ritic matrix is commonly recristallised. Euhedral dolomite ostracod foraminifera brachiopod packstone or MF 25a: rhomboeders are concentrated along stylolithic seams. cronoidal packstone) occure. At the top MF 6: nodular Macrofossils are scarce. The term “oolite” is misleading. microbioclastic Wackestone becomes more common. Ooids dominate only in the uppermost part of the unit. The upper boundary is difficult to define. The onset of They are commonly outranged by onkoids. In former stud- a intensive red colour and a pronounced nodular fabric ies this unit was regarded as a special development of the would be a good criterium for field mapping. However, “R(h)ätoliaskalk” (e.g. HELMCKE, 1974; DOERT & HELMCKE, FURRER (1993) defined the boundary at the top of the last 1976; UCHDORF, 1984: “Oolith”, “Onkoid-Mikrit” with layer enriched in crinoid debris. The grey, slightly nodular Involutina liassica JONES). A badly preseved ammonite beds above this layer are allready regarded as part of the points to Early Hettangian (FURRER, 1993). However, Adnet Limestone. holoturian sclerites indicate a still Triassic age (BAUER, In previous studies this unit was treated very controversely. 1997). Geocemical data confirm the liassic interpretation It is not shown in the lithostratigraphic columns by FURRER of the ammonite (MCROBERTs et al., 1997). (in BERTLE et al., 1979; and Fig. A25 in OBERHAUSER, 1986). The Lorüns oolite is succeeded by thickly bedded, micritic However, in the text he mentioned “Kalke, die mit lokal limestone of various colours. Pressure solution is com- angereicherten Crinoidenresten Anklänge an die Hierlatz- mon. In spite of the simmilar microfacies it differs from kalk-Fazies zeigen” (=limestone, locally enriched in cri- 10 Beiträge zur Paläontologie, 28, Wien, 2003 MEISTER, C. & FRIEBE, J.G., Austroalpine Liassic Ammonites … 11 Figure 2: The two main nappes of the studied area in the Northern Calcareous Alps of Vorarlberg. noid debris, with some similarities to Hierlatz Kalk facies), Hierlatzbasiskalk for massive to thickly bedded, brownish which have a transitional position between the Lorüns grey micrite with sponge spicula and brachiopods (MF 9: oolite beneath and the Adnet Kalk above. Later he denomi- spicula stromatactis wackestone), but without significant nated this unit as Hierlatz Kalk and defined the top of the crinoid debris beneath Hierlatz kalk s. str. (BÖHM, 1992: last crinoidal bed as its upper boundary (FURRER 1993). 63). This name was applied by LANTSCHNER (1994) for According to BÖHM (1992), however, the Hierlatz Kalk is wacke- to packstones with crinoid ossicles and sponge represented exclusively by sparitic microfacies without spicula as major constituents beneath the Adnet Kalk in larger amounts of micritic matrix. He introduced the term the Arlberg region (Vorarlberg/Tyrol). In some former studies that unit was regarded as part of the R(h)ätoliaskalk” and/ or the “Unterlias-Rotkalk” (e.g., HELMCKE,