The Bashkirian is in the ICS

geologic timescale The geologic time scale, or geological time scale, (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochronol ...

the lowest

stage Stage or stages may refer to: Acting * Stage (theatre), a space for the performance of theatrical productions * Theatre, a branch of the performing arts, often referred to as "the stage" * ''The Stage'', a weekly British theatre newspaper * Sta ...

or oldest

age Age or AGE may refer to: Time and its effects * Age, the amount of time someone or something has been alive or has existed ** East Asian age reckoning, an Asian system of marking age starting at 1 * Ageing or aging, the process of becoming older ...

of the Pennsylvanian. The Bashkirian age lasted from to Ma, is preceded by the

Serpukhovian The Serpukhovian is in the ICS geologic timescale the uppermost stage or youngest age of the Mississippian, the lower subsystem of the Carboniferous. The Serpukhovian age lasted from Ma to Ma. It is preceded by the Visean and is followed b ...

and is followed by the Moscovian. The Bashkirian overlaps with the upper part of the

Namurian The Namurian is a stage in the regional stratigraphy of northwest Europe with an age between roughly 326 and 313 Ma (million years ago). It is a subdivision of the Carboniferous system or period and the regional Silesian series. The Namurian is ...

and lower part of the Westphalian stages from regional European stratigraphy. It also overlaps with the North American Morrowan and Atokan stages and the Chinese Luosuan and lower Huashibanian stages.

Name and definition

The Bashkirian was named after Bashkiria, the then Russian name of the republic of

Bashkortostan The Republic of Bashkortostan or Bashkortostan ( ba, Башҡортостан Республикаһы, Bashqortostan Respublikahy; russian: Республика Башкортостан, Respublika Bashkortostan),; russian: Респу́блик� ...

in the southern

Ural Mountains The Ural Mountains ( ; rus, Ура́льские го́ры, r=Uralskiye gory, p=ʊˈralʲskʲɪjə ˈɡorɨ; ba, Урал тауҙары) or simply the Urals, are a mountain range that runs approximately from north to south through western ...

Russia Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...

, home of the

Bashkir people , native_name_lang = bak , flag = File:Bashkirs of Baymak rayon.jpg , flag_caption = Bashkirs of Baymak in traditional dress , image = , caption = , population = approx. 2 million , popplace ...

. The stage was introduced by Russian stratigrapher Sofia Semikhatova in 1934. The base of the Bashkirian is at the first appearance of

conodont Conodonts (Greek ''kōnos'', "cone", + ''odont'', "tooth") are an extinct group of agnathan (jawless) vertebrates resembling eels, classified in the class Conodonta. For many years, they were known only from their tooth-like oral elements, which ...

species ''Declinognathodus noduliferus''. The top of the stage (the base of the Moscovian) is at the first appearance of the conodonts ''Declinognathodus donetzianus'' or ''Idiognathoides postsulcatus'', or at the first appearance of

fusulinid The Fusulinida is an extinct order within the Foraminifera in which the tests are traditionally considered to have been composed of microgranular calcite. Like all forams, they were single-celled organisms. In advanced forms the test wall was di ...

'' Aljutovella aljutovica''. The

GSSP A Global Boundary Stratotype Section and Point (GSSP) is an internationally agreed upon reference point on a stratigraphic section which defines the lower boundary of a stage on the geologic time scale. The effort to define GSSPs is conducted b ...

( type location for the base of a stage) for the Bashkirian is in the Battleship Wash Formation at Arrow Canyon,

Nevada Nevada ( ; ) is a U.S. state, state in the Western United States, Western region of the United States. It is bordered by Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. N ...

.; 1999: ''The IUGS boundary in the middle of the Carboniferous: Arrow Canyon, Nevada, USA'', Episodes 22(4), pp 272–283.

Subdivision

The Bashkirian contains six

biozone In biostratigraphy, biostratigraphic units or biozones are intervals of geological strata that are defined on the basis of their characteristic fossil taxa, as opposed to a lithostratigraphic unit which is defined by the lithological properties of ...

s based on conodont

index fossil Biostratigraphy is the branch of stratigraphy which focuses on correlating and assigning relative ages of rock Stratum, strata by using the fossil assemblages contained within them.Hine, Robert. “Biostratigraphy.” ''Oxford Reference: Dictiona ...

s: * '' Neognathodus atokaensis'' Zone * '' Declinognathodus marginodosus'' Zone * '' Idiognathodus sinuosus'' Zone * ''Neognathodus askynensis'' Zone * '' Idiognathoides sinuatus'' Zone * ''Declinognathodus noduliferus'' Zone

References

Literature

*; 2006: ''Global time scale and regional stratigraphic reference scales of Central and West Europe, East Europe, Tethys, South China, and North America as used in the Devonian–Carboniferous–Permian Correlation Chart 2003 (DCP 2003)'', Palaeogeography, Palaeoclimatology, Palaeoecology 240(1-2): pp 318–372.

External links

Carboniferous timescale
at the website of the Norwegian network of offshore records of geology and stratigraphy

{{coord, 36.7333, N, 114.7778, W, source:wikidata, display=title Pennsylvanian geochronology