Arietenkalk 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
    • Large stone core of the index fossil     Arietites bucklandi from Ofterdingen
    Gryphaea arcuata from the Arietenkalk of the eastern Alb foreland.

    The Arietenkalk Formation is a lithostratigraphic formation of the southern German Jura. It is underlain by the Angulate Clay Formation and the Angulate Sandstone Formation and overlaid by the Obtus Clay Formation . In Franconia , it meshes with the Gryphae sandstone formation . It is dated to the Sinemurium .

    history

    The term Arietenkalk appears as early as 1843 in Friedrich August Quenstedt's work Das Flözgebirge Würtembergs . He already understood the term as lithostratigraphic.

    definition

    The Arietenkalk formation consists of gray limestone and marl, in which regional bituminous layers can also be incorporated. In the lower part, the limestone banks also contain chamositoids and regional fine sands. The thickness in Württemberg is between 2 and 22 m, in the central Upper Rhine area up to 25 m. In the southern Upper Rhine area, however, only 3 m are reached. The lower limit of the Arietenkalk Formation is marked by a (usually not very sharp) alternation between the clayey-sandy rocks of the Angulate Clay Formation and the Angulate Sandstone Formation . In Württemberg, the so-called "copper rock bank" is formed at the base of the Arietenkalk formation. The upper limit is the clay package of the Obtususton formation , at the base of which there is a rich layer, the so-called Capricornenlager, i.e. the base of the Capricornenlager forms the upper limit of the Arietenkalk Formation. Chronostratigraphically , the Arietenkalk Formation essentially comprises the Lower Sinemurium , but still extends slightly into the Upper Sinemurium.

    Breakdown

    The Arietenkalk formation is formally not further subdivided. In the base, the so-called copper rock bank is regionally eliminated, but it is not developed everywhere. Also, this term is obviously used to refer to different banks.

    Fossil guide

    The Arietenkalk Formation is known for the spectacular finds of ammonites of the genus Arietites (and closely related genera) up to over meters in size .

    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
    • Friedrich August Quenstedt: The Flözgebirge Würtembergs. With special consideration for the Jura . Laupp'sche Buchhandlung publishing house, Tübingen 1843.
    • Friedrich August Quenstedt: The Jura. Verlag der Laupp'schen Buchhandlung, Tübingen 1856–57.

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