View source for Earth:Sakmarian

{{short description|Second stage of the Permian}}
{{Infobox geologic timespan
| name                         = Sakmarian
| color                        = Sakmarian
| time_start                   = 293.52
| time_start_uncertainty       = 0.17
| time_end                     = 290.1
| time_end_uncertainty         = 0.26
| image_map                    =
| caption_map                  =
| image_outcrop                =
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<!--Chronology-->  
| timeline                     = Permian
| formerly_part_of             =
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| partially_contains           =
<!--Etymology-->
| name_formality               = Formal
| name_accept_date             =
| alternate_spellings          =
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<!--Usage Information--> 
| celestial_body               = earth
| usage                        = Global ([[Organization:International Commission on Stratigraphy|ICS]])
| timescales_used              = ICS Time Scale
| formerly_used_by             =
| not_used_by                  =
<!--Definition-->
| chrono_unit                  = Age
| strat_unit                   = Stage
| proposed_by                  =
| type_section                 =
| timespan_formality           = Formal
| lower_boundary_def           = [[Earth:First appearance datum|FAD]] of the [[Biology:Conodont|Conodont]] ''Mesogondolella monstra''
| lower_gssp_location          = Usolka section, Southern Ural mountains, {{wipe|Russia}}
| lower_gssp_coords            = {{Coord|53.9247|N|56.7287|E|display=inline}}
| lower_gssp_accept_date       = 2018<ref>{{cite journal |last1=Shen |first1=Shuzhong |title=Notes from the SPS Chair |journal=Permophile |date=August 2018 |page=4 |url=http://permian.stratigraphy.org/files/20180825094514307.pdf |access-date=12 December 2020 |issn=1684-5927}}</ref>
| upper_boundary_def           = [[Earth:First appearance datum|FAD]] of the [[Biology:Conodont|Conodont]] ''[[Biology:Sweetognathus|Sweetognathus whitei]]''
| upper_gssp_location          = Dalny Tulkas section, Southern Ural Mountains, {{wipe|Russia}}
| upper_gssp_coords            = {{Coord|53.9247|N|56.51615|E|display=inline}}
| upper_gssp_accept_date       = February 2022<ref>{{cite web |title=Ratification of Artinskian GSSP |url=https://stratigraphy.org/news/138 |website=International Commission on Stratigraphy |access-date=23 March 2022}}</ref>
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}}
In the geologic timescale, the '''Sakmarian''' is an [[Earth:Age (geology)|age]] or [[Physics:Stage (stratigraphy)|stage]] of the [[Earth:Permian|Permian]] period. It is a subdivision of the [[Earth:Cisuralian|Cisuralian]] [[Earth:Epoch (geology)|Epoch]] or [[Earth:Series (stratigraphy)|Series]]. The Sakmarian lasted between 293.52 and {{Period start|Artinskian}} [[Megaannum|million years ago (Ma)]]. It was preceded by the [[Earth:Asselian|Asselian]] and followed by the [[Earth:Artinskian|Artinskian]].<ref>{{aut|Gradstein, F.M.; Ogg, J.G. & Smith, A.G.}}; '''2004''': ''A Geologic Time Scale 2004'', Cambridge University Press</ref>

==Stratigraphy==
The Sakmarian Stage is named after the Sakmara River in the Ural Mountains, a [[Earth:Tributary|tributary]] to the Ural River. The stage was introduced into scientific literature by [[Biography:Alexander Karpinsky|Alexander Karpinsky]] in 1874. In Russian stratigraphy, it originally formed a substage of the Artinskian Stage. Currently, the [[Organization:International Commission on Stratigraphy|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 ''[[Biology:Streptognathodus|Streptognathodus]] postfusus'' in the fossil record. A global reference profile for the 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 place in the stratigraphic record where fossils of conodont species ''[[Biology:Sweetognathus|Sweetognathus]] whitei'' and ''[[Biology:Mesogondolella|Mesogondolella]] bisselli'' first appear.

== References ==
{{reflist}}

== External links ==
* [http://www.stratigraphy.org/bak/geowhen/stages/Sakmarian.html GeoWhen Database - Sakmarian]
* [http://stratigraphy.science.purdue.edu/charts/Timeslices/Upper_Paleozoic_Sept08.pdf Upper Paleozoic stratigraphic chart] at the website of the subcommission for stratigraphic information of the ICS

{{Geological history|p|p}}

[[Category:Permian geochronology]]
[[Category:Sakmarian| ]]

{{Sourceattribution|Sakmarian}}