Oligocene

The Oligocene (symbol OG) is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present (33.9±0.1 to 23.03±0.05 Ma). As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly uncertain. The name Oligocene comes from the Greek ὀλίγος (oligos, few) and καινός (kainos, new), and refers to the sparsity of additional modern mammalian species of fauna after a burst of evolution during the Eocene. The Oligocene follows the Eocene Epoch and is followed by the Miocene Epoch. The Oligocene is the third and final epoch of the Paleogene Period.

The Oligocene is often considered an important time of transition, a link between the archaic world of the tropical Eocene and the more modern ecosystems of the Miocene. Major changes during the Oligocene included a global expansion of grasslands, and a regression of tropical broad leaf forests to the equatorial belt.

The start of the Oligocene is marked by a notable extinction event; the replacement of European fauna with Asian fauna, except for the endemic rodent and marsupial families called the Grande Coupure. The Oligocene-Miocene boundary is not set at an easily identified worldwide event but rather at regional boundaries between the warmer late Oligocene and the relatively cooler Miocene.

Read more about OligoceneSubdivisions, Climate, Paleogeography, Flora, Fauna, Oceans, Impact Events, Supervolcanic Explosions

Other articles related to "oligocene":

Palaelodidae
... Three genera are recognised Adelalopus, called the "stout-legged flamingos" (Borgloon Early Oligocene of Hoogbutsel, Belgium) Palaelodus (Middle Oligocene -? Middle Pleistocene ...
Mastotermes - Fossil Record
... Late Eocene of England) Mastotermes gallica (Early Oligocene of France) Mastotermes anglicus (Middle Oligocene of England) Mastotermes electromexicus (Late Oligocene to Early Miocene Mexican amber) Mastotermes heerii (L ...
List Of Fossil Birds - Neornithes - Phoenicopteriformes
... Placement unresolved Phoeniconotius (Etadunna Late Oligocene/Early Miocene of Lake Pitikanta, Australia) Palaelodidae – Swimming-flamingos Adelalopus (Borgloon Early Oligocene ... (Middle? – Late Miocene) Extant genera present in the fossil record Phoenicopterus (middle Oligocene – Recent) ...
Archaeoceti
... suffered a heavy loss of genera during the Eocene-Oligocene extinction event, but some species survived into the Oligocene ... archaeocete, which was probably a basilosaurid, became extinct in the Oligocene ...