Valanginium

from Wikipedia, the free encyclopedia
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 Valanginium (in German often shortened to Valangin ) is a chronostratigraphic level of the Lower Cretaceous in the history of the earth . Geochronologically, it covers the period from approximately 139.3 to approximately 133.9 million years. The Valanginium follows the Berriasium and is replaced by the Hauterivium .

Naming and history

The original type locality is in the Seyon Gorge near Valangin in Switzerland ; the stage is named after this place. The stage and name were introduced by Édouard Desor in 1853.

Definition and GSSP

The stage begins with the first appearance of the Calpionellid species Calpionellites darderi and ends with the first appearance of the ammonite genus Acanthodiscus .

Breakdown

In the Tethys area, the valanginium is divided into five ammonite biozones:

The Valanginium is further divided into the Lower Valanginium and Upper Valanginium . The first appearance of the ammonite Saynoceras verrucosum defines the beginning of the Upper Valanginian , with which the significant transgression Va3 began.

literature

  • Felix Gradstein, Jim Ogg, Jim & Alan Smith: A Geologic timescale. Cambridge University Press 2005, ISBN 978-0-521-78673-7
  • Hans Murawski & Wilhelm Meyer: Geological dictionary . 10., rework. u. exp. Ed., 278, Enke Verlag, Stuttgart 1998 ISBN 3-432-84100-0 .

Web links