Stephanian (stage)
Encyclopedia
The Stephanian is a stage in the regional stratigraphy
of northwest Europe with an age between roughly 304 and 299 Ma (million years ago). It is a subdivision of the Carboniferous
system or period and the regional Silesian series
. The uppermost units of the Coal Measures
of England
and Wales
are probably of Stephanian age, though the larger part of this formation is referred to the earlier Westphalian
. The stage derives its name from the city of Saint-Étienne
in eastern central France
(which itself derives from associations with Saint Stephen
) where strata of this age occur.
In the official geologic timescale of the ICS
, the Stephanian is placed within the Pennsylvanian
epoch (318-299 Ma).
The (regionally defined) Stephanian stage corresponds to the (internationally used) Gzhelian
. References appear in scientific literature to a Stephanian epoch or Stephanian series
reflecting the stage's earlier status.
Stratigraphy
Stratigraphy, a branch of geology, studies rock layers and layering . It is primarily used in the study of sedimentary and layered volcanic rocks....
of northwest Europe with an age between roughly 304 and 299 Ma (million years ago). It is a subdivision 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"...
system or period and the regional Silesian series
Series (stratigraphy)
Series are subdivisions of rock layers made based on the age of the rock and corresponding to the dating system unit called an epoch, both being formally defined international conventions of the geological timescale. A series is therefore a sequence of rock depositions defining a...
. The uppermost units of the Coal Measures
Coal Measures
The Coal Measures is a lithostratigraphical term for the coal-bearing part of the Upper Carboniferous System. It represents the remains of fluvio-deltaic sediment, and consists mainly of clastic rocks interstratified with the beds of coal...
of England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
and Wales
Wales
Wales is a country that is part of the United Kingdom and the island of Great Britain, bordered by England to its east and the Atlantic Ocean and Irish Sea to its west. It has a population of three million, and a total area of 20,779 km²...
are probably of Stephanian age, though the larger part of this formation is referred to the earlier 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...
. The stage derives its name from the city of Saint-Étienne
Saint-Étienne
Saint-Étienne is a city in eastern central France. It is located in the Massif Central, southwest of Lyon in the Rhône-Alpes region, along the trunk road that connects Toulouse with Lyon...
in eastern central France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
(which itself derives from associations with Saint Stephen
Saint Stephen
Saint Stephen The Protomartyr , the protomartyr of Christianity, is venerated as a saint in the Roman Catholic, Anglican, Lutheran, Oriental Orthodox and Eastern Orthodox Churches....
) where strata of this age occur.
In the official geologic timescale of 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...
, the Stephanian is placed within 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...
epoch (318-299 Ma).
The (regionally defined) Stephanian stage corresponds to the (internationally used) Gzhelian
Gzhelian
The Gzhelian is an age in the ICS geologic timescale or a stage in the stratigraphic column. It is the youngest stage of the Pennsylvanian, the youngest subsystem of the Carboniferous. The Gzhelian lasted from 303.9 ± 0.9 to 299.0 ± 0.8 Ma...
. References appear in scientific literature to a Stephanian epoch or Stephanian series
Series (stratigraphy)
Series are subdivisions of rock layers made based on the age of the rock and corresponding to the dating system unit called an epoch, both being formally defined international conventions of the geological timescale. A series is therefore a sequence of rock depositions defining a...
reflecting the stage's earlier status.