Dental tone formation

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Lithostratigraphy of the South German Jura .
Abbreviations:
  • Humph.-Fm. = Humphriesioolite Formation
  • L.Bk-Fm = Lying bench lime formation
  • H.Bk-Fm = hanging bank lime formation
  • Zm-Fm = cement marl formation
  • S.-Fm = Solnhofen formation
  • Rö.-Fm = Rögling formation
  • U.-Fm = Usseltal formation
  • Mö.-Fm = Mörnshein formation
  • N.-Fm = Neuburg formation
  • R.-Fm = Rennertshofen formation

    • The Dentalienton Formation is a lithostratigraphic formation of the southern German Jura . It is underlain by the Hamitenton Formation and overlaid by the Varians Marl Formation . To the east it is laterally replaced by the Sengenthal Formation . In the Upper Rhine area it is probably represented by the main roe rock formation . At Plettenberg near Balingen (Baden-Württemberg) it reaches a maximum thickness of 36 m. It is dated in the subathonium .

    History and naming

    The term was proposed by Gert Bloos, Gerd Dietl and Günter Schweigert in 2005 for a lithostratigraphic rock formation of the southern German Jura. The term "Dentalienthon" was already used by Friedrich August Quenstedt in 1857. The name is derived from the abundant scapula in some locations , which were previously placed in the genus Dentalium . The scotchweed found in the dental clay (e.g. Laevidentalium entaloides ) are now assigned to other genera.

    Definition and distribution area

    The dental clay formation consists mainly of clay stones. The lower limit forms the upper edge of the Parkinsonieooliths, or the Upper Parkinsoniaooliths of the Hamitenton Formation . The upper limit is a middle Württemberg the base of the so-called Orbisooliths, from Gosheim to the southwest to the Wutach area, the upper limit is from the base of the sandy-marly Varian marl, which is now excreted as the Varian marl formation . Gerd Dietl specified the western slope of the Eichberg and the Buchberg in the Wutach area as the type profile. The type area is an area strip that extends a little east of Gruibingen ( Göppingen district ) to the Wutach area west of Blumberg .

    Temporal scope and structure

    The dental clay formation is stratigraphically dated into the lower bathonium, locally it possibly extends into the middle bathonium. Biostratigraphically, it essentially comprises the Zigzag Biozone, which, however, already begins in the Hamitenton Formation . The uppermost part is difficult to date biostratigraphically and could still extend into the Orbis biozone.

    The formation is divided from bottom to top into the actual dental clay, the Fuscus bank, the chondritic marl and locally the Knorri clay. The Fuscus bank is named after its characteristic ammonite Oecotraustes fuscus . The chondrite marl got its name from characteristic trace fossils ( chondrites ), and the Knorri clay is named after the small oyster Catinula knorri .

    literature

    • Gert Bloos, Gerd Dietl & Günter Schweigert: The Jura of Southern Germany in the Stratigraphic Table of Germany 2002. Newsletter on Stratigraphy, 41 (1-3): 263-277, Stuttgart 2005 ISSN  0078-0421
    • Gerd Dietl 2007. The dental formation (bt) of the Swabian Jura - description and structure. Annual books of the Society for Natural History in Württemberg, Volume 163: 5–20, Stuttgart 2007 ZDB -ID 219059-x .

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