Bashkirian
Encyclopedia
The Bashkirian is in the ICS
geologic timescale the lowest stage or oldest age of the Pennsylvanian
, the youngest subsystem of the Carboniferous
. The Bashkirian age lasted from 318.1 ± 1.3 to 311.7 ± 1.1 Ma, is preceded by the Serpukhovian
and is followed by the Moscovian
.
The Bashkirian overlaps with the upper part of the Namurian
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.
, inhabitants of the republic of Bashkortostan
in the southern Ural Mountains
(Russia
). The stage was introduced by Russian stratigrapher Sofia Semikhatova in 1934.
The base of the Bashkirian is at the first appearance of conodont
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
Aljutovella aljutovica. The GSSP (type location
for the base of a stage) for the Bashkirian is in the Battleship Wash Formation at Arrow Canyon, Nevada
.
s based on conodont index fossil
s:
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...
geologic timescale the lowest stage or oldest age of the Pennsylvanian
Pennsylvanian
The Pennsylvanian is, in the ICS geologic timescale, the younger of two subperiods of the Carboniferous Period. It lasted from roughly . As with most other geochronologic units, the rock beds that define the Pennsylvanian are well identified, but the exact date of the start and end are uncertain...
, the youngest subsystem of the Carboniferous
Carboniferous
The Carboniferous is a geologic period and system that extends from the end of the Devonian Period, about 359.2 ± 2.5 Mya , to the beginning of the Permian Period, about 299.0 ± 0.8 Mya . The name is derived from the Latin word for coal, carbo. Carboniferous means "coal-bearing"...
. The Bashkirian age lasted from 318.1 ± 1.3 to 311.7 ± 1.1 Ma, is preceded by the Serpukhovian
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 328.3 Ma tot 318.1 Ma...
and is followed by the Moscovian
Moscovian (Carboniferous)
The Moscovian is in the ICS geologic timescale a stage or age in the Pennsylvanian, the youngest subsystem of the Carboniferous. The Moscovian age lasted from 311.7 ± 1.1 to 306.5 ± 1.0 Ma, is preceded by the Bashkirian and is followed by the Kasimovian...
.
The Bashkirian overlaps with the upper part of the Namurian
Namurian
The Namurian is a stage in the regional stratigraphy of northwest Europe with an age between roughly 326 and 313 Ma . It is a subdivision of the Carboniferous system or period and the regional Silesian series. The Namurian is named for the Belgian city and province of Namur where strata of this age...
and lower part of the Westphalian
Westphalian (stage)
The Westphalian is a stage in the regional stratigraphy of northwest Europe with an age between roughly 313 and 304 Ma . It is a subdivision of the Carboniferous system or period and the regional Silesian series. The Westphalian is named for the region of Westphalia in western Germany where strata...
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 the BashkirsBashkirs
The Bashkirs are a Turkic people indigenous to Bashkortostan extending on both parts of the Ural mountains, on the place where Europe meets Asia. Groups of Bashkirs also live in the republic of Tatarstan, Perm Krai, Chelyabinsk, Orenburg, Tyumen, Sverdlovsk, Kurgan, Samara and Saratov Oblasts of...
, inhabitants of the republic of Bashkortostan
Bashkortostan
The Republic of Bashkortostan , also known as Bashkiria is a federal subject of Russia . It is located between the Volga River and the Ural Mountains. Its capital is the city of Ufa...
in the southern 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...
(Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
). The stage was introduced by Russian stratigrapher Sofia Semikhatova in 1934.
The base of the Bashkirian is at 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 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
Fusulinid
The Fusulinida is an extinct order within the Foraminifera in which the tests are composed of tightly packed, secreted microgranular calcite. In advanced forms the test wall is differentiated into two or more layers...
Aljutovella aljutovica. The GSSP (type location
Type locality (geology)
Type locality , also called type area or type locale, is the where a particular rock type, stratigraphic unit, fossil or mineral species is first identified....
for the base of a stage) for the Bashkirian is in the Battleship Wash Formation at Arrow Canyon, Nevada
Nevada
Nevada is a state in the western, mountain west, and southwestern regions of the United States. With an area of and a population of about 2.7 million, it is the 7th-largest and 35th-most populous state. Over two-thirds of Nevada's people live in the Las Vegas metropolitan area, which contains its...
.
Subdivision
The Bashkirian contains six biozoneBiozone
Biostratigraphic units or Biozones are intervals of geological strata that are defined on the basis of their characteristic fossil taxa....
s based on conodont index fossil
Index fossil
Index fossils are fossils used to define and identify geologic periods . They work on the premise that, although different sediments may look different depending on the conditions under which they were laid down, they may include the remains of the same species of fossil...
s:
- Neognathodus atokaensis Zone
- Declinognathodus marginodosus Zone
- Idiognathodus sinuosus Zone
- Neognathodus askynensis Zone
- Idiognathoides sinuatus Zone
- Declinognathodus noduliferus Zone
Literature
; 2004: A Geologic Time Scale 2004, Cambridge University Press.; 2006: The Carboniferous system, use of the new official names for the subsystems, series and stages, Geologica Acta 4(3), pp 403–407.; 1999: The IUGS boundary in the middle of the Carboniferous: Arrow Canyon, Nevada, USA, Episodes 22(4), pp 272–283.; 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.; 1999: Bashkirian conodonts of the Donets Basin, Ukraine. Scr. Geol. 119, pp 1–115 .; 1986: Zonal fusulinid scale of the Moscovian Stage based on a revision of the type sections of intrastage subdivisions, Vopr. Mikropaleontol. 28, pp 3–23 .External links
- Carboniferous timescale at the website of the Norwegian network of offshore records of geology and stratigraphy
- Bashkirian, Geowhen Database