Gashatan
The Gashatan is in Earth's history, a regional level in the terrestrial Paleogene of East Asia. The Gashatan is the second step in the sequence of Landsäugetierfaunen in East Asia and following the Nongshanian. It is detached from the Bumbanian. The Gashatan is correlated with the upper Thanetium ( Paleocene, Paleogene ) of the chronostratigraphic division of the earth's history.
Naming and history
The stage has already been proposed by Romer (1966 ), but not defined. It is named after the locality Gashato (Inner Mongolia ) and the fauna found there fossil land mammals.
Definition, correlation and absolute dating
The base of the stage is defined by the Ersteinsetzen the type Tribosphenomys minutus ( Alagomyidae, Glires, mammals). In addition Hyaenodontidae put a ( Creodonta ) Coryphodontidae ( Pantodonta ) Dinocerata, Rodentiaformes, Carpolestidae and Nyctitheriidae. The representatives of the Mesonychidae ( Mesonychia ) and Pastoralodontidae take significantly to body size.
The stage is being correlated with the upper part of the global level of the upper Thanetium Paleocene. In absolute terms, it is the period from 57.3 to 56 Ma.
The Gashatan corresponds to the North American Landsäugetierstratigraphie ( NALMA ) probably the Cliffordian and the highest part of Tiffanian. However, the correlation is still very uncertain. By Wang et al. (2007) includes the Gashatan the Cliffordian and a greater share of the Tiffanian (as in the Time Scale Creator correlation). The Gashatan is not further subdivided.