Sakmarian

In the geologic timescale, the Sakmarian is an age or stage of the Permian. It is a subdivision of the Cisuralian epoch or series. The Sakmarian lasted between 294.6 ± 0.8 and 284.4 ± 0.7 million years ago (Ma). It was preceded by the Asselian and followed by the Artinskian.[1]

Stratigraphy

The Sakmarian stage is named after the Sakmara River in the Ural Mountains, a tributary to the Ural River. The stage was introduced into scientific literature by Alexander Karpinsky in 1874. In Russian stratigraphy, it originally formed a substage of the Artinskian stage. Currently, the ICS uses it as an independent stage in its international geologic timescale.

The base of the Sakmarian stage is laid with the first appearance of conodont species Streptognathodus postfusus in the fossil record. A global reference profile for the base (a GSSP) had in 2009 not yet been appointed. The top of the Sakmarian (the base of the Artinskian) is defined as the place in the stratigraphic record where fossils of conodont species Sweetognathus whitei and Mesogondolella bissell first appear.

References

Notes

1. ^ See Gradstein et al. (2004) for a detailed geologic timescale

Literature

* Gradstein, F.M.; Ogg, J.G. & Smith, A.G.; 2004: A Geologic Time Scale 2004, Cambridge University Press

External links

* GeoWhen Database - Sakmarian
* Upper Paleozoic stratigraphic chart at the website of the subcommission for stratigraphic information of the ICS