Paleogene
| < Chalk | P ales | Neogene > about 65.5–23.03 million years ago |
|||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Atmospheric O 2 share (average over period) |
approx. 26 vol .-% (130% of today's level) |
||||||||||||||||||||||||||||||||||
|
Atmospheric CO 2 share (average over period) |
approx. 500 ppm (125% of today's level) |
||||||||||||||||||||||||||||||||||
| Floor temperature (average over period) |
approx. 18 ° C (4 ° C above today's level) |
||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||
The paleogene (from ancient Greek παλαιός palaiós , German 'old' and γένος génos 'descent, age') is the lowest chronostratigraphic system and the oldest geochronological period of the Cenozoic and lasted from about 66 million years ago to the beginning of the Neogene about 23, 03 million years ago. Palaeogene and Neogene used to be combined to form the tertiary system . The term "tertiary" is no longer used by the International Commission on Stratigraphy (ICS) and paleogene and neogene are now used in the hierarchical rank of systems.
At the beginning of the Paleogene, after the extinction of the non-avian dinosaurs, there was further development of the birds and a considerable differentiation of the mammals , which from formerly small forms became the dominant land animals in the past Cretaceous . Towards the end of the Paleogene, the proboscis were the largest land mammals. The individual continents were initially isolated. However , the animals were able to spread widely again via a land bridge between Africa and Eurasia , which formed 27 million years ago. Only Australia and Antarctica developed differently.
Subdivision
The paleogene is further divided into:
-
System : Paleogene (66–23.03 mya )
- Series : Oligocene (33.9–23.03 mya)
- Series: Eocene (56–33.9 mya)
- Level: Priabonium (38-33.9 mya)
- Stage: Bartonium (41.3–38 mya)
- Stage: Lutetium (47.8-41.3 mya)
- Level: Ypresium (56-47.8 mya)
- Series: Paleocene (66–56 mya)
- Level: Thanetium (59.2–56 mya)
- Level: Seelandium (61.6-59.2 mya)
- Level: Danium (66-61.6 mya)
Paleogeography
In the paleogene the continents took roughly their present positions. North and South America were not yet connected by Central America, and Africa and Eurasia were still separated by the continuously narrowing Tethys . Australia and Antarctica had already separated, but were still close to each other. The Indian plate collided with the Eurasian and the Himalayas formed . Large areas of North America, Eurasia and Africa silted up, and the island world of Europe slowly began to form a coherent area of land.
