Berriasium

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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 Berriasium (in German usage also shortened to Berrias , more rarely also Berriasias) is the oldest chronostratigraphic level of the Lower Cretaceous in the history of the earth . On the geochronological time scale, the stage corresponds to the period from approximately 145 to 139.3 million years. The Berriasium follows the Tithonium (youngest stage of the Jurassic ) and is replaced by the Valanginium .

Naming and history

The step is after the place Berrias in French department Ardèche named. The level and name were introduced into scientific literature by Henri Coquand in 1869 . In the past, the stage in the transition from Jura to Lower Cretaceous in northern Germany was also known as Wealden .

Definition and GSSP

The beginning of the stage is (presumably) defined by the first appearance of the ammonite species Berriasella jacobi . A GSSP (global type locality and type profile) has not yet been defined. The end of the stage is also only provisionally determined with the first appearance of the Calpionella species Calpionellites darderi . No GSSP has yet been defined for the base of the Valanginium either. The ammonite species Thurmanniceras pertransiens also sets in just a little above the targeted Berriasium / Valanginium border .

Subdivision of the Berriasium

The Berriasium in the Tethyalen area is divided into four ammonite biozones:

Individual evidence

  1. ↑ Discussions about the Jurassic-Cretaceous boundary (Part I) by Ph.J. Hoedemaeker

literature

  • Felix Gradstein, Jim Ogg, Jim & Alan Smith: A geologic time scale. Cambridge University Press 2005, ISBN 0-521-78673-8
  • Hans Murawski & Wilhelm Meyer: Geological dictionary . 10., rework. u. exp. Ed., 278, Enke Verlag, Stuttgart 1998 ISBN 3-432-84100-0 .

Web links