The Visean, Viséan or Visian is an

age Age or AGE may refer to: Time and its effects * Age, the amount of time someone has been alive or something 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 geochron ...

or a

stage Stage, stages, or staging may refer to: Arts and media 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 Brit ...

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 is exp ...

of the

Carboniferous The Carboniferous ( ) is a Geologic time scale, geologic period and System (stratigraphy), system of the Paleozoic era (geology), era that spans 60 million years, from the end of the Devonian Period Ma (million years ago) to the beginning of the ...

. The Visean lasted from to Ma. It follows the

Tournaisian The Tournaisian is in the ICS geologic timescale the lowest stage or oldest age of the Mississippian, the oldest subsystem of the Carboniferous. The Tournaisian age lasted from Ma to Ma. It is preceded by the Famennian (the uppermost st ...

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 ...

age/stage.

Name and definitions

The Viséan Stage was introduced by Belgian geologist André Dumont in 1832. Dumont named this stage after the city of

Visé Visé (; , ; ) 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, and Visé. In the ...

in Belgium's

Liège Province Liège ( ; ; ; ; ) 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 Dutch province of Limburg, the ...

. Before being used as an international stage, the Viséan 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 331 and 319 Ma (million years ago). It is a subdivision of the Carboniferous system or period, as well as the regional Silesian series. The Na ...

Stage. In the North American regional scale, the Viséan Stage correlates with the upper

Osagean 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 rou ...

, the

Meramecian The Meramecian or Maramec stage is a sequence of Mississippian rocks in the Mississippi River Valley. It is named for the Meramec River in Missouri. Members Included are the St. Louis Limestone, Ste. Genevieve Limestone, Salem Limestone, and the ...

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 rough ...

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 i ...

.; 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 d ...

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 Dinant () is a City status in Belgium, city and Municipalities in Belgium, municipality of Wallonia located in the Namur Province, province of Namur, Belgium. On the shores of river Meuse, in the Ardennes, it lies south-east of Brussels, south ...

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), sometimes referred to as a golden spike, is an internationally agreed upon reference point on a stratigraphic section which defines the lower boundary of a stage on the geologic time scale. ...

has been proposed in the

Luzhai Formation Luzhai County (; Standard Zhuang: ) is under the administration of Liuzhou, Guangxi Zhuang Autonomous Region, China. The easternmost county-level division of Liuzhou City, it borders the prefecture-level cities of Guilin Guilin (Standard Zhua ...

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" and "caring" while the character ''xi'' 系 mean ...

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

conodont Conodonts, are an extinct group of marine jawless vertebrates belonging to the class Conodonta (from Ancient Greek κῶνος (''kōnos''), meaning " cone", and ὀδούς (''odoús''), meaning "tooth"). They are primarily known from their hard ...

'' Lochriea ziegleri'', 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 taxon, taxa, as opposed to a Lithostratigraphy, lithostratigraphic unit which is defined by the ...

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) su ...

'' Cravenoceras leion''.

Biota

The

Carboniferous-Earliest Permian Biodiversification Event The Carboniferous ( ) is a geologic period and system of the Paleozoic era that spans 60 million years, from the end of the Devonian Period Ma (million years ago) to the beginning of the Permian Period, Ma. It is the fifth and penultimate period ...

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

metazoa Animals are multicellular, eukaryotic organisms in the biological kingdom Animalia (). With few exceptions, animals consume organic material, breathe oxygen, have myocytes and are able to move, can reproduce sexually, and grow from a hol ...

reef A reef is a ridge or shoal of rock, coral, or similar relatively stable material lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic component, abiotic (non-living) processes such as deposition (geol ...

s 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 (stratigraphy), stage in the Devonian Period (roughly 358.9 ± 0.4 million y ...

. One of the

tetrapod A tetrapod (; from Ancient Greek :wiktionary:τετρα-#Ancient Greek, τετρα- ''(tetra-)'' 'four' and :wiktionary:πούς#Ancient Greek, πούς ''(poús)'' 'foot') is any four-Limb (anatomy), limbed vertebrate animal of the clade Tetr ...

s that lived during the Visean age was ''

Westlothiana ''Westlothiana'' ("animal from West Lothian") is a genus of reptile-like tetrapods that lived about 338 million years ago during the latest part of the Viséan age of the Carboniferous. The genus is known from a single species, ''Westlothiana liz ...

'', a

reptile Reptiles, as commonly defined, are a group of tetrapods with an ectothermic metabolism and Amniotic egg, amniotic development. Living traditional reptiles comprise four Order (biology), orders: Testudines, Crocodilia, Squamata, and Rhynchocepha ...

-like

amphibian Amphibians are ectothermic, anamniote, anamniotic, tetrapod, four-limbed vertebrate animals that constitute the class (biology), class Amphibia. In its broadest sense, it is a paraphyletic group encompassing all Tetrapod, tetrapods, but excl ...

. Though originally thought to be the earliest discovered

amniote Amniotes are tetrapod vertebrate animals belonging to the clade Amniota, a large group that comprises the vast majority of living terrestrial animal, terrestrial and semiaquatic vertebrates. Amniotes evolution, evolved from amphibious Stem tet ...

, 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 z ...

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 (geology), Mississippian (also known as Lower Carboniferous), contains eight conodont biozon ...

bilineatus'' Zone * ''

texanus'' Zone In British stratigraphy, the Visean is subdivided into five substages. From youngest to oldest, these are:; 2006: ''The Carboniferous system, use of the new official names for the subsystems, series and stages'', Geologica Acta 4(3), pp 403–407. * Brigantian * Asbian * Holkerian * Arundian * Chadian (the lower part of this substage falls in the Tournaisian)

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