The Rupel Formation (abbreviation: RU) is a

geologic formation 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 exp ...

in the

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 ...

of the

Netherlands ) , anthem = ( en, "William of Nassau") , image_map = , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of the Netherlands , established_title = Before independence , established_date = Spanish Netherl ...

that consists of

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the ...

marine Marine is an adjective meaning of or pertaining to the sea or ocean. Marine or marines may refer to: Ocean * Maritime (disambiguation) * Marine art * Marine biology * Marine debris * Marine habitats * Marine life * Marine pollution Military * ...

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

s and

clay Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4). Clays develop plasticity when wet, due to a molecular film of water surrounding the clay par ...

s. The Rupel Formation is part of the Middle North Sea Group and correlates exactly with the Belgian Rupel Group.

Name

The Rupel Formation was first described by André Hubert Dumont in 1849. The formation is taken from Belgian lithostratigraphy, although it is considered a group in Belgium. The

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 which the formation formed is the Rupelian (34 to 28 million years ago), a subdivision of the Oligocene epoch. The age and the formation are both named after the Belgian river Rupel.

Facies and lithologies

The Rupel Formation can be 250 meters thick at maximum. During the Rupelian age the Netherlands (and Belgium) were covered by a shallow sea, which became deeper towards the northwest. In the northwest, the sedimentary facies can be more than 500 m deep marine, while in southeastern parts of the Netherlands the formation has a near coastal facies. The formation is subdivided in four members: the Bilzen Member (yellow-white glauconiferous fine sand, containing fossils), the Boom Member (a thick clay deposit, containing

loam Loam (in geology and soil science) is soil composed mostly of sand (particle size > ), silt (particle size > ), and a smaller amount of clay (particle size < ). By weight, its mineral composition is about 40–40–20% concentration of sand–sil ...

layers and septaria), the Eigenbilzen Member (strongly layered sands) and the Ratum Member (sand, clay and loam, appears only in the east of the Netherlands).

Stratigraphy

In the southwest of the Netherlands the Rupel Formation lies stratigraphically on top of the late

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

to early Oligocene

Tongeren Formation The Tongeren Formation ( nl, Formatie van Tongeren; abbreviation: TO) is a geologic formation in the subsurface of the Netherlands. The formation consists of shallow marine, epicontinental and continental sediments, predominantly clay and sand from ...

. Further east the Rupel Formation is found on top of the Eocene sands of the Dongen Formation. In the east, on the Middel-Netherlands High, the base of the formation can also be a nonconformity with

Mesozoic The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceo ...

deposits. In some places the younger

Veldhoven Formation The Veldhoven Formation ( nl, Formatie van Veldhoven; 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 Veldhove ...

lies on top of the Rupel Formation. In other places the top of the Rupel Formation is a

hiatus Hiatus may refer to: *Hiatus (anatomy), a natural fissure in a structure *Hiatus (stratigraphy), a discontinuity in the age of strata in stratigraphy *''Hiatus'', a genus of picture-winged flies with sole member species ''Hiatus fulvipes'' *Globa ...

, on which

Neogene The Neogene ( ), informally Upper Tertiary or Late Tertiary, is a geologic period and system that spans 20.45 million years from the end of the Paleogene Period million years ago ( Mya) to the beginning of the present Quaternary Period Mya. ...

formations (such as the

Breda Formation The Breda Formation ( nl, Formatie van Breda; abbreviation: BR) is a geologic formation in the subsurface of the Netherlands. The formation consists of marine glauconiferous sands and clays that were deposited during the Miocene epoch. Although ...

or Naaldwijk Formation) can be found.

References

* (''eds.''); 1993: ''Stratigraphic nomenclature of the Netherlands, revision and update by RGD and NOGEPA'', Mededelingen Rijks Geologische Dienst 50, pp. 1–39 *; 1849: ''Rapport sur la Carte géologique du Royaume'', Bulletin de l'Académie royale de Belgique 16 (2^ième partie), p. 370 () *; 1975: ''Lithostratigrafie van de Mio-Oligocene afzettingen in Zuid-Limburg'', in: (''eds.''): ''Toelichting bij geologische overzichtskaarten van Nederland'', Rijks Geologische Dienst, Haarlem, pp. 56–63. ()

External links

* ; 2003
Formatie van Rupel
TNO website ({{in lang, nl) Geologic formations of the Netherlands Oligocene Series of Europe Paleogene Netherlands