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Sakmarian

Sakmarian
293.52 ± 0.17 – 290.1 ± 0.26 Ma
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Chronology
Etymology
Name formalityFormal
Usage information
Celestial bodyEarth
Regional usageGlobal (ICS)
Time scale(s) usedICS Time Scale
Definition
Chronological unitAge
Stratigraphic unitStage
Time span formalityFormal
Lower boundary definitionFAD of the Conodont Mesogondolella monstra
Lower boundary GSSPUsolka section, Southern Ural Mountains, Russia
53°55′29″N 56°43′43″E / 53.9247°N 56.7287°E / 53.9247; 56.7287
Lower GSSP ratified2018[2]
Upper boundary definitionFAD of the Conodont Sweetognathus whitei
Upper boundary GSSPDalny Tulkas section, Southern Ural Mountains, Russia
53°55′29″N 56°30′58″E / 53.9247°N 56.51615°E / 53.9247; 56.51615
Upper GSSP ratifiedFebruary 2022[3]

In the geologic timescale, the Sakmarian is an age or stage of the Permian period. It is a subdivision of the Cisuralian Epoch or Series. The Sakmarian lasted between 293.52 and 290.1 million years ago (Ma). It was preceded by the Asselian and followed by the Artinskian.[4]

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 (International Commission on Stratigraphy) uses it as an independent stage in its international geologic timescale.

The base of the Sakmarian Stage is defined by the first appearance of conodont species Streptognathodus postfusus in the fossil record. A global reference profile for the stage's base (a GSSP), located in the southern Ural Mountains, Russia, was ratified in 2018. The top of the Sakmarian (the base of the Artinskian) is defined as the level in the stratigraphic record where fossils of conodont species Sweetognathus whitei and Mesogondolella bisselli first appear.

References

  1. ^ "International Chronostratigraphic Chart" (PDF). International Commission on Stratigraphy. September 2023. Retrieved November 10, 2024.
  2. ^ Shen, Shuzhong (August 2018). "Notes from the SPS Chair" (PDF). Permophile: 4. ISSN 1684-5927. Retrieved 12 December 2020.
  3. ^ "Ratification of Artinskian GSSP". International Commission on Stratigraphy. Retrieved 23 March 2022.
  4. ^ Gradstein, F.M.; Ogg, J.G. & Smith, A.G.; 2004: A Geologic Time Scale 2004, Cambridge University Press
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