In the geologic timescale, the Sakmarian is an age or stage of the Permian

Permian

The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...

. It is a subdivision of the Cisuralian epoch

Epoch (geology)

An epoch is a subdivision of the geologic timescale based on rock layering. In order, the higher subdivisions are periods, eras and eons. We are currently living in the Holocene epoch...

 or series

Series (stratigraphy)

Series are subdivisions of rock layers made based on the age of the rock and corresponding to the dating system unit called an epoch, both being formally defined international conventions of the geological timescale. A series is therefore a sequence of rock depositions defining a...

. The Sakmarian lasted between 294.6 ± 0.8 and 284.4 ± 0.7 million years ago (Ma). It was preceded by the Asselian

Asselian

In the geologic timescale, the Asselian is the earliest geochronologic age or lowermost chronostratigraphic stage of the Permian. It is a subdivision of the Cisuralian epoch or series. The Asselian lasted between 299.0 ± 0.8 and 294.6 ± 0.8 million years ago...

 and followed by the Artinskian

Artinskian

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 lasted between 284.4 ± 0.7 and 275.6 ± 0.7 million years ago...

.

Stratigraphy

The Sakmarian stage is named after the Sakmara River

Sakmara River

Sakmara River is a river in Russia that drains the southern tip of the Ural Mountains south into the Ural River. Its length is . It is a tributary of the Ural River, which it meets in Orenburg. The source of the Sakmara River is in the Republic of Bashkortostan...

 in the Ural Mountains

Ural Mountains

The Ural Mountains , or simply the Urals, are a mountain range that runs approximately from north to south through western Russia, from the coast of the Arctic Ocean to the Ural River and northwestern Kazakhstan. Their eastern side is usually considered the natural boundary between Europe and Asia...

, a tributary

Tributary

A tributary or affluent is a stream or river that flows into a main stem river or a lake. A tributary does not flow directly into a sea or ocean...

 to the Ural River

Ural River

The Ural or Jayıq/Zhayyq , known as Yaik before 1775, is a river flowing through Russia and Kazakhstan. It arises in the southern Ural Mountains and ends at the Caspian Sea. Its total length is 1,511 mi making it the third longest river in Europe after the Volga and the Danube...

. 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

The International Commission on Stratigraphy , sometimes referred to by the unofficial "International Stratigraphic Commission" is a daughter or major subcommittee grade scientific daughter organization that concerns itself with stratigraphy, geological, and geochronological matters on a global...

 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

Conodont

Conodonts are extinct chordates resembling eels, classified in the class Conodonta. For many years, they were known only from tooth-like microfossils now called conodont elements, found in isolation. Knowledge about soft tissues remains relatively sparse to this day...

 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.

External links

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