Eocene

The Eocene is in Earth's history, a chronostratigraphic series ( = time interval) within the Paleogene. The Eocene began about 56 million years ago and ended about 33.9 million years and is the second series of the Paleogene (see Geologic time scale). The Eocene was followed by the Oligocene and preceded the Paleocene.

Naming and history

Named the Eocene after the Greek goddess of the dawn Eos, Greek ἔος or ἠώς and Greek καινός = " new, unusual ". The name was coined by Charles Lyell in 1847.

Definition and GSSP

The base of the Eocene ( and Ypresium ) is a marked change in the carbon isotope ratio ( "Carbon Isotope Excursion "). The upper limit (and therefore the lower limit of Oligocene and Rupelium ) is defined by the extinction of the foraminiferal genus Hantkenina. The GSSP ( = global calibration point ) of the Eocene (and the Ypresium stage) is the Dababiya profile near Luxor ( Egypt).

Subdivision

The Eocene is divided into three sub-series and four stratigraphic levels:

• Series: Eocene ( 56 to 33.9 mya ) Subseries: Upper Eocene (or Upper Eocene ) Level: Priabonium ( 38 to 33.9 mya )

• Level: Bartonium ( 41.3 to 38 mya )
• Level: Lutetium ( 47.8 to 41.3 mya )

• Level: Ypresium ( 56 to 47.8 mya )

Regional and see the historical context and found a whole series of other steps use names that have been used or abandoned either regionally for various reasons.

Climate and geography

The beginning of the Eocene is marked by a strong rise in temperature, the Paleocene / Eocene Thermal Maximum, which was caused by a strong increase in carbon dioxide concentration in the atmosphere. Throughout the Eocene, the climate was too warm to allow glaciation at the poles; both Greenland and Antarctica were ice-free. South America and Australia were both Antarctica closer than today, the Antarctic Circumpolar Current was formed only in the later Oligocene. The Atlantic Ocean was not yet fully open, the end of the Paleocene Greenland and Europe drifted apart - but it was still a land bridge between Eurasia, Greenland and the North American continent.

Faunal

Important in the Eocene is the sudden development of mammals. The orders of the odd-toed ungulates, bats, primates and rodents originated.

Fossil sites

Among the most famous sites of Eocene Messel Pit in Germany are near Darmstadt (Hesse), the Geisel valley near Halle (Saale ) (Saxony -Anhalt ) and the corner squares Maar at Manderscheid ( Rhineland -Palatinate). There, they found fossil remains of insects, amphibians, reptiles, birds and mammals. At this exotic wildlife included, among other things, giant ants, giant snakes, crocodiles, up to two meters high giant ratite Diatryma, fox large ancestral horses, tapirs, anteaters, pangolins, Urraubtiere and the bipedal Leptictida.