Sakmarian

System/
Period		 Series/
Epoch		 Stage/
Age		 Age (Ma)
Triassic Lower/
Early		 Induan younger
Permian Lopingian Changhsingian 251.902 254.14
Wuchiapingian 254.14 259.1
Guadalupian Capitanian 259.1 265.1
Wordian 265.1 268.8
Roadian 268.8 272.95
Cisuralian Kungurian 272.95 283.5
Artinskian 283.5 290.1
Sakmarian 290.1 295.0
Asselian 295.0 298.9
Carboniferous Pennsylvanian Gzhelian older
Subdivision of the Permian system
according to the ICS, as of 2017.[1]

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 295 and 290.1 million years ago (Ma). It was preceded by the Asselian and followed by the Artinskian.[2]

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 bisselli first appear.

Palaeontology

Amphibians

Amphibians of the Sakmarian
Taxa Presence Location Description Images
Boskovice Furrow, Czech Republic
Abo Formation, New Mexico and Seymour, Baylor County, Texas

Synapsids

Synapsids of the Sakmarian
Taxa Presence Location Description Images

Sakmarian-Kungurian

Greene Formation, Ohio; Belle Plains Formation, Texas; Cutler Formation, Utah, all in the USA
locality 3, Cutler Formation, San Miguel County, Colorado, USA
Kasimovian-Kungurian

Kenilworth, Kenilworth Sandstone Formation, Warwickshire Group, Warwickshire, England; Autun, France, Cutler Formation, Arizona, Colorado, New Mexico and Utah; Fort riley, Chase Group, Kansas, Greene Formation, Dunkard Group, Ohio; Wellington Formation, Oklahoma; Clyde Formation, Texas and Oklahoma; Admiral Formation; Belle-Plains Formation; Wichita Group; Putnam Formation, all four in Texas,

Niederhäslich locality, Dresden, Niederhäslich Limestone Member, Niederhäslich Formation, Rotliegend Group, Döhlen Basin, Saxony, Germany
Gzhelian-Artinskian New Mexico; Utah-Arizona border region, USA; possibly England The English specimen known as S?. brittanicus ) is now generally classified as Sphenacodontidae incertae sedis separate from the other Sphenacodon species so may need reassigning.

References

  1. ↑ http://www.stratigraphy.org/index.php/ics-chart-timescale
  2. ↑ Gradstein, F.M.; Ogg, J.G. & Smith, A.G.; 2004: A Geologic Time Scale 2004, Cambridge University Press
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.