Aptium

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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 Aptian (in German usage shortened only called Apt, more rarely Aptien) is in the Earth's history the name of a stratigraphic level in the upper sub chalk . It lasted geochronologically from about 126.3 million years ago to about 112.9 million years ago. The Aptium follows the Barremium and is replaced by the Albium .

Naming and history

The Aptium is named after the small French town of Apt in Provence , near which the level's original type locality is located. The stage and name were introduced by Alcide Dessalines d'Orbigny in 1840.

Definition and GSSP

The beginning of the stage is defined by the base of the magnetic anomaly M0 , the end by the first appearance of the coccolithophore species Praediscosphaera columnata . A GSSP ( global type locality and type profile ) has not yet been finally ratified.

Breakdown

In Tethysbereich the level in eight will Ammonites - biozones divided:

Locally, the level is divided into the following three sub-levels: Bedoulium (lower aptium), Gargasium (middle aptium) and Clansayesium (upper aptium).

particularities

Remnants of the crocodile Sarcosuchus imperator, which can be up to 12 m long, date back to the time of the transition from the uppermost Aptium to the lower Albium in Niger .

literature