Maastrichtium

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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 Maastrichtium (in German often shortened to Maastricht) is the highest and most recent chronostratigraphic level of the Upper Cretaceous in the history of the earth . In absolute numbers ( geochronologically ) the stage covers the period from about 72 to about 66 million years. The Maastrichtian follows the Campanium , it is replaced by the Danium (formerly placed in the chalk), the oldest stage of the Paleogene and thus the Cenozoic (Earth Modern Age).

At the end of the Maastrichtian lies the Cretaceous-Paleogene border , which documents one of the largest global mass extinctions in the history of the earth and a dramatic faunal cut associated with it.

Naming and history

The stage is named after the Dutch city ​​of Maastricht . The stage and name were proposed by André Hubert Dumont in 1849.

Definition and GSSP

The base is defined with the first appearance of the ammonite species Pachydiscus neubergicus , the upper limit is marked by an iridium anomaly , which is also correlated with a mass extinction of various animal groups ( foraminifera , calcareous nannoplankton, dinosaurs , ammonites, belemnites, etc.). The GSSP is located in Grande Carrière, Tercis-les-Bains , Landes department , south-west France (coordinate: 43 ° 40 ′ 46 ″  N , 1 ° 6 ′ 48 ″  W ).

Breakdown

Two lower levels are planned for the Maastrichtium: Unter- and Obermaastrichtium

In the Tethys area, the Maastrichtian is divided into three ammonite zones (from young to old):

Fauna and flora development

The Cretaceous and thus the Mesozoic Era ended with the Maastrichtian . The following period is the Paleogene , which is already counted to the Cenozoic. The turn from the Cretaceous to the Paleogene is still often called after the older term " Tertiary " for the beginning of the Cenozoic era Cretaceous-Tertiary border . This is characterized by a mass extinction , to which a large part of the animal and plant world of that time fell victim. The cause is assumed to be the impact of a large meteorite or extremely strong volcanism . The chalk-Tertiary boundary also falls with a strong marine retreat together (marine regression). As a result, large areas of the shelf that were still covered by shallow seas in the Campanian and at the beginning of the Maastrichtian period fell dry, and the habitat of many inhabitants of the shallow water disappeared.

literature

  • Felix Gradstein, Jim Ogg, Alan Smith: A Geologic Timescale. 3. Edition. Cambridge University Press, Cambridge 2006, ISBN 978-0-521-78673-7 .
  • Hans Murawski, Wilhelm Meyer: Geological dictionary. 10th edition. Enke, Stuttgart 1998, ISBN 3-432-84100-0 .
  • D. B. Weishampel et al. a. (Ed.): The Dinosauria . 2nd Edition. University of California Press, Berkeley 2004, pp. 517-606 ( Dinosaur distribution chapter ).

Web links