Amaltheenton Formation

from Wikipedia, the free encyclopedia
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
    • Amaltheenton, rift of the Pliensbach near Zell unter Aichelberg

    The Amaltheenton Formation is a lithostratigraphic formation in the southern German Jura region (Swabian Alb, Upper Rhine Graben, Alpine Foreland, Franconian Alb) and in northern Germany. It is correlated with the higher part of the international chronostratigraphic level of the Pliensbachium (Oberpliensbachium or Domerium ). The maximum thickness in southern Germany is> 68 m, in the Reitbock-Leversen borehole (northern Germany) 175 m. The Amatheenton Formation is underlain by the Numismalis Marl Formation and overlaid by the Posidonia Schist Formation .

    history

    The term Amaltheenton goes back to Friedrich August Quenstedt , who coined it in 1856/7. In the Quenstedt division of the southern German Jura, the Amaltheenton or the Amaltheenton Formation is assigned to the Lias Delta.

    definition

    The Amaltheenton Formation consists predominantly of pyrite-rich, dark to black-gray silty clay stones, clay marl stones with clay iron lumps, pyrite and lime concretions . In the south of the distribution area and in the Ries area, fine sandy clay stones and clay marl stones can also occur. In the area of ​​the Swabian Alb, also called Swabian facies, one or more light gray limestone banks , the so-called Costatenkalk , occur in the upper part of the formation ; "Echinoderm debris limestone" also occurs. The limestone banks are bioturbated and in some areas merge laterally into layers of limestone nodules.

    On the Franconian Alb, the so-called Franconian facies, predominantly dark clay stones with gray limestone lumps can be found. These lime nodules are often sidereal and therefore weather brown. Eastern Bavaria is already near the former edge of the basin. Here the formation also contains thin layers of iron oliths.

    In northern Germany, on the other hand, black-gray and lime-poor mudstones predominate. They are often fluffy, fine sand, and the frequency of flasers increases towards the northeast. Regional, e.g. B. in Emsland, bituminous sedimentary rocks can also occur.

    To the west and northwest, it merges into the Aalburg Formation and the Ida Formation . In the Prignitz and Havelland (Brandenburg) - only proven by drilling - the Amaltheenton Formation merges to the east into the more sandy Komorowo Formation , which extends further to Poland. To the northeast follows the lower Sorthat formation under the Baltic Sea and in Bornholm . In northern Switzerland, the Rickenbach member of the Staffelegg formation corresponds to the Amaltheenton formation.

    Limits

    The lower limit is defined with the beginning of the claystone over the limestone marl of the Numismalis marl formation, which is presumably somewhat heterochronous. The upper limit is determined by the upper edge of the so-called Costaten bank or banks. On the Franconian Alb the upper limit is with the onset of the bituminous facies of the Posidonia schist formation. The Amaltheenton Formation covers most of the Oberpliensbachian with the ammonite zones of Amaltheus margaritatus and Pleuroceras spinatum .

    Chronostratigraphically, the Amaltheenton Formation begins somewhat differently with the upper limit of the Davoei Zone and within different levels of the Stokesi and Subnodosus subzones of the lower Margaritatus Zone . In the distribution area, however, the two zones have a different thickness to one another. In southwest Germany, the Margaritatus Zone is significantly thicker than the relatively condensed, thin Spinatum Zone . In the Franconian Alb, on the other hand, the Spinatum zone is significantly thicker than the thin Margaritatus zone. The key abbreviation of the State Office for Geology, Raw Materials and Mining (Baden-Württemberg) for the Amaltheenton Formation in geological maps is pb2.

    Breakdown

    The Amaltheenton Formation is divided into the Amaltheenton proper and the Costatenkalk subformation (2-3 m thickness) at the top of the formation.

    literature

    • Friedrich August Quenstedt: The Flözgebirge Wuerttemberg. Laupp Publishing House, Tübingen 1843.
    • 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. In: Newsletters on Stratigraphy. Vol. 41, No. 1/3, 2005, ISSN  0078-0421 , pp. 263-277.
    • Eckhard Mönnig: The Jura of Northern Germany in the Stratigraphic Table of Germany 2002. Newsletters on Stratigraphy, 41 (1-3): 253-261, Stuttgart 2005 ISSN  0078-0421
    • Lithostratigraphic units of Germany: Amaltheenton Formation

    Web links