Astaracian

The Astaracium is a regional level in the terrestrial Neogene of Europe. It corresponds to the zone MN 6 and 7/ 8 of the European land mammal chronology ( ELMMZ = " European Land Mammal Mega - Zones" ). It is underlain by Orleanium and overlaid by Vallesium.

History and type locality

The stage is named after the ancient county Astarac. The region lies today in the northern part of the Department Hautes -Pyrénées ( France). The type locality, the fossil deposit Sansan, located in the Val de Gers (France)

Definition

The lower limit is defined by the onset of large mammal species Tethytragus, Hispanomeryx, Euprox and Listriodon. For small mammals, there are the types Megacricetodon crusafonti, Megacricetodon Gerši. The stage ends (or begins Vallesium ) with the first appearance of the genera Hippotherium, Decennatherium and Machairodus ( large mammals ) and of Cricetulodon among small mammals. The stage is correlated with the stages of the chronostratigraphic Langhium, the Serravallium and the lowermost part of Tortonium. This corresponds in geochronology the period of 15 to 11.1 million years.

Subdivision

The stage is divided into three biozones MN 6 to 8, wherein the zones are 7/8 usually combined. Occasionally, the stage is divided into lower and upper Astaracium, the lower the biozone Astaracium MN 6 and the upper Astaracium the biozone 7/8 corresponds.