Artinskien

In the geologic timescale, the Artinskian is an age or stage of the Permian. It is a subdivision of the Cisuralian Epoch or Series. The Artinskian likely lasted between and million years ago (Ma) according to the most recent revision of the International Commission on Stratigraphy (ICS) in 2022. It was preceded by the Sakmarian and followed by the Kungurian. The Artinskian is named after the goniatite grits of Artinsk which was introduced by Roderick Murchison, Édouard de Verneuil and count Alexander von Keyserling in their "The Geology of Russia in Europe and the Ural Mountains" (1845). The grits of Artinsk, in turn, get its name from the Artinsky District with center in the Russian smalltown of Arti (formerly Artinsk zavod), situated in the middle Urals, about 170 km southwest of Yekaterinburg. The stage was introduced into scientific literature by Alexander Karpinsky in 1874. The base of the Artinskian Stage is defined as the first appearance datum (FAD) of the conodont species Sweetognathus whitei and Mesogondolella bisselli. In order to constrain this age, the ICS subcommission on Permian stratigraphy informally proposed a candidate GSSP in 2002, later followed by a formal proposal in 2013. The proposed GSSP location — the Dal'ny Tulkas roadcut in the Southern Urals, near the town of Krasnousolsky — was eventually ratified in February 2022. U-Pb radiometric dating found that the base of the Artinskian was approximately 290.1 million years old (Ma), based on the position of the rock layer at the Dal'ny Tulkas roadcut containing the FAD of S. whitei relative to three precisely dated ash beds surrounding it. Earlier radiometric reported a much younger age of 280.3 Ma for the Sakmarian-Artinskian boundary. The top of the Artinskian (and the base of the Kungurian) is defined as the place in the stratigraphic record where fossils of conodonts Neostreptognathodus pnevi and Neostreptognathodus exculptus first appear. The proposed GSSP candidate — the Mechetlino section (Southern Urals).