Carnian

The Carnian, ( in German usage almost always shortened to Karn ) is in Earth 's oldest (lowest ) took chronostratigraphic stage of the Upper Triassic, the geochronological corresponds to the period before about 235 to about 228 million years, during which approximately 12.2 million years. The previous stage is the stage following the Norian Ladinium the Middle Triassic.

Naming and history

Edmund of Mojsisovics introduced the name in 1869 as " Carnian stage " a. Is not entirely clear whether the name from the Carnic Alps ( Austria ) or rather from the Latin name for Carinthia ( = Carinthia ) is derived.

Definition and GSSP

The beginning of the stage is defined by the first appearance of the ammonite species Daxatina canadensis. The official GSSP (global type locality and type profile) is the profile in the Stuores Meadows in Badia ( Bolzano, South Tyrol). The end of the level is set primitius through the base of the ammonite zone Klamathites macrolobatus or Stikinoceras kerri and by the conodont zones Metapolygnathus communisti or Metapolygnathus. The final border demarcation (or the GSSP for the Norian ) has not yet been ratified.

Subdivision

The Carnian is divided into five ammonite zones:

  • Anatropites spinosus Zone
  • Tropites subbullatus zone
  • Tropites dilleri zone
  • Austrotrachyceras austriacum zone
  • Trachyceras zone

Regionally, the Karn is in the lower grades Cordevolian ( Cordevolium ), divided in July ( Julium ) and Tuval ( Tuvalium ).

Credentials

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