Impression 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 Impressamergel Formation (formerly only Imprintamgel or Impressakalke, also Cardiocerate layers) is a lithostratigraphic formation of the southern German Jura . It is underlain by the Ornate Clay Formation and overlaid by the Well-Stratified Limestone Formation . It interlocks laterally with the hole formation and reaches a maximum thickness of 25 to 125 m. It is dated to the Oxfordium (to the Lower Kimmeridgian ?).

    history

    The term was proposed by Gert Bloos, Gerd Dietl and Günter Schweigert in 2005 for a lithostratigraphic rock formation. The name goes back to the term Impressakalke introduced by Friedrich August Quenstedt in 1857. The name is derived from the armwort Terebratula impressa (today Aulacothyris impressa ).

    Definition and distribution area

    The Impressamergel formation comprises dark gray to light gray limestone marl with some limestone banks embedded in it. The lower limit is relatively well defined by the change in color (from “brown” to “white” Jura). The upper limit is formed by the insertion of the wall-like stratified limestone of the well- stratified limestone formation . It interlocks with the hole formation , especially in the higher part, and is increasingly being replaced by this formation. In the Upper Rhine Valley it is represented by the Kandern Formation , the Coral Limestone Formation and the Nerine Limestone Formation . The distribution of the Impressamergel formation extends over the entire Swabian Alb to the Wutach area.

    Temporal scope and breakdown

    The Impressamergel formation begins in the cordatum zone of the higher Unteroxfordium. The upper limit is diachronous and extends locally into the Epipeltoceras bimammatum zone (upper oxfordium to the lowest lower kimmeridgium). It is subdivided from bottom to top into three subformations: Transversarium subformation, Effingen subformation and Bimammatum subformation. In the Wutach area the Transversarium subformation is replaced by the Birmensdorf subformation.

    swell

    literature

    • Gert Bloos, Gerd Dietl, Günter Schweigert: The Jura of Southern Germany in the Stratigraphic Table of Germany 2002. In: Newsletters on Stratigraphy. Vol. 41, No. 1/3, 2005, ISSN  0078-0421 , pp. 263-277.
    • Friedrich August Quenstedt: The Jura. Laupp Publishing House, Tübingen 1856–57.

    Individual evidence

    1. ↑ Hydrogeological units of the hydrogeological overview map 1: 500,000. (PDF; 40 kB) Freiburg Regional Council - State Office for Geology, Raw Materials and Mining, accessed on November 16, 2014 .

    Web links