Murchisonaeoolith 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 Murchisonaeoolith Formation is a lithostratigraphic formation of the southern German Jura. It is only developed in the Upper Rhine Valley and is the equivalent there for the Eichberg Formation in the Wutach area and for the iron sandstone formation in the Swabian Alb. The Murchisonaeoolith Formation is underlain by the Opalinus Clay Formation and overlaid by the Wedelsandstone Formation . The thickness of the Murchisonae oolite varies between 10 and 30 m. It is dated to the Oberaalenium .

    history

    The term Murchisonae oolite was already used by Quenstedt (1856–57). It is named after the ammonite Ludwigia murchisonae (Sowerby) and was equated by Quenstedt with his Braunjura beta. It is now defined as a formation ; a type locality has not yet been determined.

    Chrono- and biostratigraphic classification

    The Murchisonaeoolith Formation is dated to the Upper Aalenium of the Middle Jurassic series. The formation includes max. the biozones of Ludwigia murchisonae , Brasilia bradfordensis and Graphoceras concavum .

    Lithology and subdivision

    The Murchisonaeoolith Formation consists of light, yellowish to gray limestone or iron oolites as well as sandy limestone and calcareous sandstones. It is subdivided into the Comptum Bank, the Lying Sand Limestone, the actual Murchisonae Oolite and the Concava Sandstone Bank.

    Economical meaning

    Due to the iron content, it was mined in several places above and below ground, z. B. Kahlenberg near Ringsheim (north of Freiburg im Breisgau ) until 1969.

    literature

    • Friedrich August Quenstedt: The Jura. Laupp Publishing House, Tübingen 1856–57.
    • 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

    Web links