The Serpukhovian is in 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...

 geologic timescale the uppermost stage or youngest age of the Mississippian, the lower 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 Serpukhovian age lasted from 328.3 (± 1.6) Ma tot 318.1 (± 1.3) Ma. It is preceded by the Visean

Viséan

The Visean, Viséan or Visian is an age in the ICS geologic timescale or a stage in the stratigraphic column. It is the second stage of the Mississippian, the lower subsystem of the Carboniferous. The Visean lasted from 345.3 ± 2.1 to 328.3 ± 1.6 Ma...

 and is followed by the Bashkirian

Bashkirian

The Bashkirian is in the ICS geologic timescale the lowest stage or oldest age of the Pennsylvanian, the youngest subsystem of the Carboniferous...

.

The Serpukhovian correlates with the lower 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...

 stage of European stratigraphy and the middle and upper parts of the Chesterian stage of North American stratigraphy.

Name and definition

The Serpukhovian stage was proposed in 1890 by Russian stratigrapher Sergei Nikitin and was introduced in the official stratigraphy of European Russia in 1974. It was named after the city of Serpukhov

Serpukhov

Serpukhov is a city in Moscow Oblast, Russia, which is situated at the confluence of the Oka and the Nara Rivers. It is located south from Moscow on the Moscow—Simferopol highway. The Moscow—Tula railway passes through the town. Population: -History:...

, near Moscow

Moscow

Moscow is the capital, the most populous city, and the most populous federal subject of Russia. The city is a major political, economic, cultural, scientific, religious, financial, educational, and transportation centre of Russia and the continent...

. The ICS later used the upper Russian subdivisions of the Carboniferous in its international geologic time scale.

The base of the Serpukhovian is at the first appearance of the 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...

 Lochriea crusiformis. In 2007, no GSSP had been assigned to the Serpukhovian stage yet. The top of the stage (the base 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...

 subsystem and Bashkirian stage) is at the first appearance of the conodont Declinognathodus nodiliferus. It is also slightly above the first appearance of the foram

Foraminifera

The Foraminifera , or forams for short, are a large group of amoeboid protists which are among the commonest plankton species. They have reticulating pseudopods, fine strands of cytoplasm that branch and merge to form a dynamic net...

 Globivalvulina bulloides, genozone of the ammonoid genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 Homoceras and the ammonoid biozone

Biozone

Biostratigraphic units or Biozones are intervals of geological strata that are defined on the basis of their characteristic fossil taxa....

 of Isohomoceras subglobosum.

Subdivision

The Serpukhovian stage includes four conodont biozones:

• Gnathodus postbilineatus Zone
• Gnathodus bollandensis Zone
• Lochriea cruciformis Zone
• Lochriea ziegleri Zone

In Russian stratigraphy, the Serpukhovian is subdivided into three substages, from bottom to top: Tarusian, Steshevian, and Protvian. In British stratigraphy, the Serpukhovian (lower Namurian) contains three substages. These are from bottom to top: Pendleian, Arnsbergian and Chokierian (only the lower Chokierian falls in the Serpukhovian, the top falls in the Bashkirian).

Literature

; 2009: Early Bashkirian Rugosa (Anthozoa) from the Donets Basin, Ukraine. Part 1. Introductory considerations and the genus Rotiphyllum Hudson, 1942, Acta Geologica Polonica 59(1), pp. 1–37.; 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.; 1890: Carboniferous deposits of the Moscow region and artesian waters near Moscow, Trudy Geologicheskogo Komiteta 5(5), pp. 1–182 .

External links

• Carboniferous timescale at the website of the Norwegian network of offshore records of geology and stratigraphy
• Serpukhovian, Geowhen Database
• The Serpukhovian age, www.palaeos.com