Lacunosam Gel 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 Lacunosamergel (formerly only "Lacunosamergel" or "Lacunosaschichten", also "Ataxioceratenschichten") is a lithostratigraphic formation of the southern German Jura . It is underlain by the Well Stratified Limestone Formation and overlaid by the Lower Rock Limestone Formation and the Mass Limestone Formation . It interlocks laterally with the Lochen Formation and Schwarzbach Formation and reaches a maximum thickness of approx. 20 to over 70 m. It is dated in the Kimmeridgium .

    history

    The term was proposed by Herbert Schick in 2004 for a lithostratigraphic rock formation in the White Jura . The name goes back to the term "Lacunosaschichten" introduced by Friedrich August Quenstedt in 1843. It is derived from the arm pod Terebratula lacunosa .

    Definition and distribution area

    The Lacunosamergel Formation comprises an alternating layer of gray marls and marl limestone. The lower limit is characterized by the onset of gray, micritic limestone banks and marls. In the border area there are ammonite enrichments, layers with the trace fossil chondrites and layers that are characterized by a content of dark green, granular glauconite . The distribution area is the Swabian Alb. In the east the Lacunosamergel formation ends at the Ries. In the west it goes over to the Schwarzbach formation near Geisingen . The type profile is on the southern flank of the Michelsberg, approx. 500 m northeast of Hausen an der Fils (City of Bad Überkingen , district of Göppingen ).

    Temporal scope and breakdown

    The Lacunosamergel Formation is subdivided into four subformations with ten distinctive banks (or layers): Hausen Subformation (with lower and upper Placunosamgeln), Michelsberg Subformation (with Polyplocus Marl and Tenuilobatus Marl), Ueberkingen Subformation (with the Planular Marl and Lacnosabänken ) and Drackenstein subformation (with the balderum banks and two progeronia banks). The Lacunosamergel Formation comprises three ammonite zones: Platynota, Hypselocyclum and Divisum zones. This corresponds to the Lower and Middle Kimmeridgian .

    swell

    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 Jura. Laupp Publishing House, Tübingen 1856–57.
    • Herbert Schick: Structure and type profile of the Lacunosamergel formation (Upper Jura, Swabian Alb). Stuttgart Contributions to Natural History, Series B, 346: 1-25, Stuttgart 2004 PDF

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