The Namurian is a stage in the regional

stratigraphy Stratigraphy is a branch of geology concerned with the study of rock layers ( strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy has three related subfields: lithost ...

of northwest Europe with an age between roughly 326 and 313 Ma (million years ago). It is a subdivision of the

Carboniferous 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 ''Carboniferou ...

system 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 express ...

or period and the regional Silesian series. The Namurian is named for the

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 ...

city and province of

Namur Namur (; ; nl, Namen ; wa, Nameur) is a city and municipality in Wallonia, Belgium. It is both the capital of the province of Namur and of Wallonia, hosting the Parliament of Wallonia, the Government of Wallonia and its administration. Na ...

where strata of this age occur (part of the Belgian Coal Measures). The Millstone Grit Group in the

lithostratigraphy Lithostratigraphy is a sub-discipline of stratigraphy, the geological science associated with the study of strata or rock layers. Major focuses include geochronology, comparative geology, and petrology. In general, strata are primarily igneous ...

of northern

England England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe ...

and parts of

Wales Wales ( cy, Cymru ) is a country that is part of the United Kingdom. It is bordered by England to the east, the Irish Sea to the north and west, the Celtic Sea to the south west and the Bristol Channel to the south. It had a population in ...

is also of Namurian age. The Namurian age lasted from 326 to 313 million years ago. It is preceded by the Visean stage/age (which corresponds to the upper

Carboniferous Limestone Carboniferous Limestone is a collective term for the succession of limestones occurring widely throughout Great Britain and Ireland that were deposited during the Dinantian epoch (geology), Epoch of the Carboniferous period (geology), Period. T ...

of Great Britain) and succeeded by the Westphalian stage/age (which corresponds to the lower and middle

Coal Measures In lithostratigraphy, the coal measures are the coal-bearing part of the Upper Carboniferous System. In the United Kingdom, the Coal Measures Group consists of the Upper Coal Measures Formation, the Middle Coal Measures Formation and the Lower Coa ...

of Great Britain). In the official

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 ...

of the

International Commission on Stratigraphy The International Commission on Stratigraphy (ICS), sometimes referred to unofficially as the "International Stratigraphic Commission", is a daughter or major subcommittee grade scientific daughter organization that concerns itself with stratigr ...

(ICS), the Namurian straddles the boundary between the Mississippian epoch (359-318 Ma) and the Pennsylvanian epoch (318-299 Ma). The upper part of the (regionally defined) Namurian stage corresponds to the (internationally used)

Bashkirian The Bashkirian is in the ICS geologic timescale the lowest stage or oldest age of the Pennsylvanian. The Bashkirian age lasted from to Ma, is preceded by the Serpukhovian and is followed by the Moscovian. The Bashkirian overlaps with the ...

stage whilst the lower part is assigned to the preceding Serpukhovian stage. Frequent references appear in scientific literature to a Namurian epoch or Namurian series reflecting the stage's earlier status.

References

Carboniferous geochronology . Mississippian geochronology Pennsylvanian geochronology Stratigraphy of Europe Namur (city) Namur (province) {{geochronology-stub