The Middle North Sea Group (abbreviation: NM) is a

group A group is a number of persons or things that are located, gathered, or classed together. Groups of people * Cultural group, a group whose members share the same cultural identity * Ethnic group, a group whose members share the same ethnic iden ...

geologic formations A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics (lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock expo ...

in the

Dutch Dutch or Nederlands commonly refers to: * Something of, from, or related to the Netherlands ** Dutch people as an ethnic group () ** Dutch nationality law, history and regulations of Dutch citizenship () ** Dutch language () * In specific terms, i ...

subsurface In geology, bedrock is solid rock that lies under loose material (regolith) within the crust of Earth or another terrestrial planet. Definition Bedrock is the solid rock that underlies looser surface material. An exposed portion of bedro ...

, part of the

North Sea Supergroup North is one of the four compass points or cardinal directions. It is the opposite of south and is perpendicular to east and west. ''North'' is a noun, adjective, or adverb indicating direction or geography. Etymology The word ''north'' is ...

. The three formations of this group form a thick sequence of sediments in the Dutch subsurface, they crop out in parts of the southern Netherlands. The Middle North Sea Group was deposited from the late

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

to late

Oligocene The Oligocene ( ) is a geologic epoch (geology), epoch of the Paleogene Geologic time scale, Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that defin ...

, between 37 and 23 million years ago. Its three formations are (from old to young) the

Tongeren Tongeren (; ; ; ) is a city and former municipality located in the Belgian province of Limburg, in the southeastern corner of the Flemish region of Belgium. Tongeren is the oldest town in Belgium, as the only Roman administrative capital wit ...

Rupel The Rupel () is a tidal river in northern Belgium, right tributary of the Scheldt. It is about long. It flows through the Belgian province of Antwerp. It is formed by the confluence of the rivers Dijle and Nete, in Rumst. It flows into the Sch ...

and

Veldhoven Formation The Veldhoven Formation (; abbreviation: VE) is a geologic formation in the subsurface of the Netherlands. The formation consists of an alternation of marine clay and sand from the Oligocene epoch. Lithology The Veldhoven Formation has a shallow ...

s. The Tongeren Formation has a

continent A continent is any of several large geographical regions. Continents are generally identified by convention (norm), convention rather than any strict criteria. A continent could be a single large landmass, a part of a very large landmass, as ...

al to paralic

facies In geology, a facies ( , ; same pronunciation and spelling in the plural) is a body of rock with distinctive characteristics. The characteristics can be any observable attribute of rocks (such as their overall appearance, composition, or con ...

, the other two consist mainly of shallow marine

clay Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolinite, ). Most pure clay minerals are white or light-coloured, but natural clays show a variety of colours from impuriti ...

s and

sand Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is usually defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural ...

References

Geologic groups of Europe Geologic formations of the Netherlands Lithostratigraphy of the Netherlands {{Europe-geologic-formation-stub