Paleocene

The Paleocene, in professional publications as Paleocene (analog engl. Paleocene ) transcribed in the Earth's history, a time interval, the lowest stratigraphic series (or epoch in the geochronology ) the Paleogene ( early Tertiary ). The Paleocene started about 66 million years ago and ended about 56 million years ago. It's between the Cretaceous, the last system of the Mesozoic era ( Mesozoic ), and classified the Eocene.

Naming and history

After the initial allocation of the Tertiary in the three series Eocene, Miocene and Pliocene by Charles Lyell led Wilhelm Philipp Schimper 1847 palaeobotanist as a further subdivision of the Paleocene one. Schimper worked at Strasbourg University and wrote his works in French. The transcription of the introduced by him in the geology of the word " Paleocene " is the German controversial, often also spelled " Paleocene " will take the form " Paleocene " is used. The latter goes back to the view, Schimper have the name of the substantiated by the period " Paleocene " from " pal ( éo ) -" and " Eocene " (ie in the meaning " Old - Eocene " ) contracted. In the context of Schimpers work but there is more evidence that he " paléo - " ( from Greek παλαιός = old) and " Cène " has formed (new, unusual from the Greek καινός =) the term of the components, so end up like the other epochs of the Cenozoic on " ZÄN ". In this view, the notation " Paleocene " now mainly used in the German language is based. The Stratigraphic Table of Germany 2002, however, used the spelling Paleocene. However, it remains to be seen whether this decision is in favor of the spelling Paleocene against Paleocene finally fallen.

Definition and GSSP

The lower limit of the Paleocene ( and thus of the Paleogene and the Danian ) is the top of the iridium anomaly in the Cretaceous-Tertiary boundary. The upper limit ( and thus also the base of the Eocene and Ypresium ) is ( "Carbon isotope Escursion " ) is defined by a change in the carbon isotope ratio. The GSSP of the Paleocene ( and thus also the GSSP of Paleogene and Danian ) is a profile in El Kef in Tunisia.

Subdivision

The Paleocene is in three stratigraphic levels

• System: Paleogene ( 66 to 23.03 mya ) Series: Oligocene ( 33.9 to 23.03 mya )
• Series: Eocene ( 56 to 33.9 mya )
• Series: Paleocene ( 66-56 mya ) Level: Thanetium ( 59.2 to 56 mya )
• Level: Seelandium ( 61.6 to 59.2 mya )
• Level: Danian ( 66 to 61.6 mya )

Subdivided. Regional quite a number of other steps were proposed, which were either used only regionally or could not enforce an internationally recognized levels.

Distribution of continents

The face of the earth was different due to the different distribution of the continents in the Paleocene yet clear from the present appearance. At the beginning of the epoch some fragments of the old southern continent Gondwana were still connected. So Australia and South America were still connected to Antarctica, Africa and India but further north already isolated. Between these southern continents and the northern Laurasia the Tethys lay like a belt around the Earth. North America was connected with Europe and Greenland had across the Bering Strait with East Asia contact. But there was a shallow sea that Turgai road that connected the Tethys Sea to the Arctic Ocean, between Europe and Asia.

Climate and vegetation

At the beginning of the Paleocene temperatures were lower than in the previous Cretaceous period by about 2 to 3 degrees, later in the period it increased slightly to. The climate was generally much warmer and wetter than today. In Greenland and Patagonia thrived subtropical vegetation and the poles were temperate climate. At the end of the Paleocene, there was a global, sudden rise in temperature of about 5-6 ° C. The Late Paleocene Thermal Maximum was triggered by a sudden release of carbon or carbon dioxide. As a source become unstable methane hydrate are discussed on the seabed or thawing permafrost. The rise in temperature took place in a period of 1000 or less years. The return to the previous state of the climate lasted about 200,000 years.

Fauna of the Paleocene

Characterized the Paleocene is characterized by the development of the formerly small mammals, which increased in size and species after the extinction of non-avian dinosaurs at the border of Upper Cretaceous to Paleocene. Even the birds reached a worldwide distribution.