Astaracium
The Astaracium is a regional stage in the terrestrial neogene of Europe. It corresponds to zones MN 6 and 7/8 of the European land mammal chronology ( ELMMZ = "European Land Mammal Mega-Zones"). It is underlain by the Orleanium and overlaid by the Vallesium .
History and type locality
The stage is named after the ancient county of Astarac . The area is now in the northern part of the Hautes-Pyrénées ( France ). The type locality, the Sansan fossil deposit , is located in the Val de Gers (France)
definition
The lower limit is defined by the onset of the large mammal genera Tethytragus , Hispanomeryx , Euprox and Listriodon . In the small mammals it is the species Megacricetodon crusafonti , Megacricetodon gersi . The stage ends (or the Vallesium begins) with the first appearance of the genera Hippotherium , Decennatherium and Machairodus (large mammals) as well as Cricetulodon in the small mammals. The stage is correlated with the chronostratigraphic stages of the Langhium , the Serravallium and the lowest part of the Tortonium . In geochronology, this corresponds to the period from 15 to 11.1 million years.
Breakdown
The stage is subdivided into three bio-zones MN 6 to 8, with zones 7/8 mostly being combined. Occasionally the level is also divided into a lower and an upper astaracium, with the lower astaracium corresponding to biozone MN 6 and the upper astaracium corresponding to biozone 7/8.
literature
- J. Agustí, L. Cabrera, M. Garcés, W. Krijgsman, O. Oms, JM Parés: A calibrated mammal scale for the Neogene of Western Europe. State of the art. Earth Science Reviews, 52: 247-260, Amsterdam 2001 ISSN 0012-8252
- Everett Lindsay: Eurasian mammal biochronology: an overview. Palaeogeography, Palaeoclimatology, Palaeoecology, 133: 117-128, Amsterdam 1997 ISSN 0031-0182