Cenomanium

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system series step ≈ age ( mya )
higher higher higher younger
chalk Upper Chalk Maastrichtium 66
⬍
72
Campanium 72
⬍
83.6
Santonium 83.6
⬍
86.3
Coniacium 86.3
⬍
89.7
Turonium 89.7
⬍
93.9
Cenomanium 93.9
⬍
100.5
Lower Cretaceous Albium 100.5
⬍
112.9
Aptium 112.9
⬍
126.3
Barremium 126.3
⬍
130.7
Skin rivium 130.7
⬍
133.9
Valanginium 133.9
⬍
139.3
Berriasium 139.3
⬍
145
deeper deeper deeper older

The Cenomanian (usually shortened as Cenomanian called) is in the Earth's history , the lowermost chronostratigraphic stage of the Upper Cretaceous . Geochronologically, the stage covers the period from about 100.5 to about 93.9 million years. The Cenomaniac follows the Albium (Lower Cretaceous) and is replaced by the Turonium .

At the end of the cenomancy an oceanic anoxic event took place, which was named after its first descriptor Guido Bonarelli in Italian Livello Bonarelli (Bonarelli horizon), English Cenomanian Turonian Boundary Event .

Naming and history

The original type locality is near Le Mans ( Département Sarthe , France). The (new) Latin name of Le Mans is Cenomanum and the stage name is derived from this. The name and geological stage were suggested by Alcide Dessalines d'Orbigny in 1847.

Definition and GSSP

The base of the stage is defined by the first appearance of the foraminifera species Rotalipora globotruncanoides . The stage ends with the first appearance of the ammonite species Watinoceras devonense . Important key fossils for the Cenomanium are the ammonite species Calycoceras naviculare , Acanthoceras rhotomagense and Mantelliceras mantelli . The GSSP (global calibration point) is 36 m below the top of the Marnes-Bleues formation on Mont Risou , Rosans , Hautes-Alpes department in south-east France (44 ° 23'33 "N, 5 ° 30'43" E).

Important fossils

With Argentinosaurus and Giganotosaurus , the largest known (but extinct) land creatures were discovered in the corresponding formations in Argentina. → Candeleros formation

literature

  • Felix Gradstein, James Ogg, Alan Gilbert Smith: A Geologic timescale. Cambridge University Press, Cambridge, UK 2005, ISBN 0-521-78673-8 .
  • Hans Murawski, Wilhelm Meyer: Geological dictionary. 10. Edit again u. exp. Edition. Enke Verlag, Stuttgart 1998, ISBN 3-432-84100-0 .
  • Thomas Meyer: Biostratigraphic and sedimentological investigations in the plan facies of the Cenoman of northwest Germany. In: Messages from the Geological Institute of the University of Hanover. Issue 30. Hannover 1990, ISSN  0440-2812 .
  • German Stratigraphic Commission, Manfred Menning (Hrsg.): Stratigraphische Tisch von Deutschland 2002 . Potsdam 2002, ISBN 3-00-010197-7 (1 sheet, Stratigraphie.de [PDF; 6.6 MB ]).

Web links