The Visean, Viséan or Visian is an

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 ...

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 geochr ...

or a

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 ...

in the

stratigraphic column A stratigraphic column is a representation used in geology and its subfield of stratigraphy to describe the vertical location of rock units in a particular area. A typical stratigraphic column shows a sequence of sedimentary rocks, with the oldest ...

. It is the second stage of the Mississippian, the lower

subsystem A system is a group of interacting or interrelated elements that act according to a set of rules to form a unified whole. A system, surrounded and influenced by its environment, is described by its boundaries, structure and purpose and expresse ...

of the Carboniferous. The Visean lasted from to Ma. It follows the

Tournaisian The Tournaisian 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 ...

age/stage and is followed 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 ...

age/stage.

Name and definitions

The Viséan Stage was introduced by

Belgian Belgian may refer to: * Something of, or related to, Belgium * Belgians, people from Belgium or of Belgian descent * Languages of Belgium, languages spoken in Belgium, such as Dutch, French, and German *Ancient Belgian language, an extinct languag ...

geologist

André Dumont André Dumont may refer to: * André Dumont (geologist) * André Dumont (politician) André Dumont (24 May 1764 at Oisemont – 19 October 1838 at Abbeville), was a French parliamentarian, a regicide, a deputy of the National Convention, Pres ...

in 1832. Dumont named this stage after the city of

Visé Visé (; nl, Wezet, ; wa, Vizé) is a city and municipality of Wallonia, located on the river Meuse in the province of Liège, Belgium. The municipality consists of the following districts: Argenteau, Cheratte, Lanaye, Lixhe, Richelle ...

in Belgium's

Liège Province Liège (; wa, Lîdje ; nl, Luik ; german: Lüttich ) is the easternmost province of the Wallonia region of Belgium. Liège Province is the only Belgian province that has borders with three countries. It borders (clockwise from the north) the Du ...

. Before being used as an international stage, the Visean Stage was part of the (West) European regional geologic time scale, in which it followed the Tournaisian Stage and is followed by 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 ...

Stage. In the North American regional scale, the Visean Stage correlates with the upper Osagean, the Meramecian and lower

Chesterian The Mississippian ( , also known as Lower Carboniferous or Early Carboniferous) is a subperiod in the geologic timescale or a subsystem of the geologic record. It is the earlier of two subperiods of the Carboniferous period lasting from roughly ...

stages. In the Chinese regional time scale, it correlates with the lower and middle Tatangian

series Series may refer to: People with the name * Caroline Series (born 1951), English mathematician, daughter of George Series * George Series (1920–1995), English physicist Arts, entertainment, and media Music * Series, the ordered sets used in ...

.; 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. The base of the Viséan Stage is at the first appearance of the

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 dif ...

species '' Eoparastaffella simplex'' (

morphotype In biology, polymorphism is the occurrence of two or more clearly different morphs or forms, also referred to as alternative ''phenotypes'', in the population of a species. To be classified as such, morphs must occupy the same habitat at the s ...

1/morphotype 2). The type locality for the stage base used to be in a road section below the castle of Dinant in Belgium, but this type locality proved to be insufficient for the purpose of stratigraphic correlation. A

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 ...

has been proposed in the Luzhai Formation near Penchong in the Chinese province of

Guanxi ''Guanxi'' () is a term used in Chinese culture to describe an individual's social network of mutually beneficial personal and business relationships. The character ''guan'', 关, means “closed” while the character ''xi'' 系 means “system ...

. The top (the base of the Serpukhovian and Namurian) is laid at the first appearance of the conodont ''

Lochriea ziegleri ''Lochriea'' is an extinct genus of conodonts. Use in stratigraphy The Visean, the second age of the Mississippian, contains four conodont biozones, two of which are named after ''Lochriea'' species: * the zone of ''Lochriea nodosa'' * the ...

'', or at the base of the

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 ...

goniatite Goniatids, informally goniatites, are ammonoid cephalopods that form the order Goniatitida, derived from the more primitive Agoniatitida during the Middle Devonian some 390 million years ago (around Eifelian stage). Goniatites (goniatitids) survi ...

'' Cravenoceras leion''.

Biota

The

Carboniferous-Earliest Permian Biodiversification Event The Carboniferous ( ) is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period million years ago ( Mya), to the beginning of the Permian Period, million years ago. The name ''Carbonifero ...

began in the Viséan, coinciding with the start of the main phase of the Late Palaeozoic Ice Age. The late Viséan saw the widespread reappearance of metazoan reefs after their devastation during the

Hangenberg Event The Hangenberg event, also known as the Hangenberg crisis or end-Devonian extinction, is a mass extinction that occurred at the end of the Famennian stage, the last stage in the Devonian Period (roughly 358.9 ± 0.4 million years ago). It is usuall ...

. One of the tetrapods that lived during the Visean age was ''

Westlothiana ''Westlothiana'' ("animal from West Lothian") is a genus of reptile-like tetrapod that lived about 338 million years ago during the latest part of the Visean age of the Carboniferous. Members of the genus bore a superficial resemblance to modern ...

'', a reptile-like amphibian. Though originally thought to be the earliest discovered amniote, more recent research has cast doubt on this interpretation.

Biostratigraphy

The Visean contains four conodont biozones: * ''

Lochriea ''Lochriea'' is an extinct genus of conodonts. Use in stratigraphy The Visean, the second age of the Mississippian, contains four conodont biozones, two of which are named after ''Lochriea'' species: * the zone of ''Lochriea nodosa'' * the ...

nodosa'' Zone * ''

mononodosa'' Zone * ''

Gnathodus ''Gnathodus'' is an extinct conodont genus in the family Idiognathodontidae. Use in stratigraphy The Tournaisian, the oldest age of the Mississippian (also known as Lower Carboniferous), contains eight conodont biozones, 3 of which are defi ...

bilineatus'' Zone * ''

texanus'' Zone In British stratigraphy, the Visean is subdivided into five substages. These are from bottom to top: Chadian (the lower part of this substage falls in the Tournaisian), Arundian,

Holkerian The Holkerian is a sub-stage of the Viséan stage of the International Commission on Stratigraphy (ICS) geological timescale. It is one of five sub-stages commonly used in the Viséan stage within stratigraphy by British, Irish and other geologists ...

, Asbian and Brigantian.; 2006: ''The Carboniferous system, use of the new official names for the subsystems, series and stages'', Geologica Acta 4(3), pp 403–407.

References

External links

Upper
an
lower
time scales for the Carboniferous at the website of the Norwegian network of offshore records of geology and stratigraphy

www.palaeos.com {{DEFAULTSORT:Visean Mississippian geochronology Geological ages . Stratigraphy of Europe

Name and definitions

Biota

Biostratigraphy

References

Further reading

External links