The Rupel Group is a

stratigraphic group In geology, a group is a lithostratigraphic unit consisting of a series of related formations that have been classified together to form a group. Formations are the fundamental unit of stratigraphy. Groups may sometimes be combined into super ...

rock strata In geology and related fields, a stratum ( : strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as ei ...

in the subsurface of

Belgium Belgium, ; french: Belgique ; german: Belgien officially the Kingdom of Belgium, is a country in Northwestern Europe. The country is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeast, France to th ...

. It is subdivided into three formations that are all

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 * ...

deposits (sands and clays) 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 ...

age.

Name

The Rupel Group was first named by Belgian geologist

André Hubert Dumont André — sometimes transliterated as Andre — is the French and Portuguese form of the name Andrew, and is now also used in the English-speaking world. It used in France, Quebec, Canada and other French-speaking countries. It is a variation ...

in 1849. It shares its name with the

Rupelian The Rupelian is, in the geologic timescale, the older of two ages or the lower of two stages of the Oligocene Epoch/Series. It spans the time between . It is preceded by the Priabonian Stage (part of the Eocene) and is followed by the Chattian ...

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 ...

(34 to 28 million years ago) of the

geological 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 geochrono ...

. Both group and age are named after the Belgian river

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 Sche ...

. The Rupel Group corresponds with the Rupel Formation in 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 ...

Facies and lithologies

The Rupel Group can be 250 meters thick at maximum. During the Rupelian age Belgium was covered by a shallow sea. The formations of the Rupel Group therefore have a shallow marine to near coastal facies.

Stratigraphy

The group is subdivided into three formations: the Bilzen Formation (yellow-white glauconiferous fine sand, containing fossils), the Boom Formation (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 A concretion is a hard, compact mass of matter formed by the precipitation of mineral cement within the spaces between particles, and is found in sedimentary rock or soil. Concretions are often ovoid or spherical in shape, although irregular ...

) and the Eigenbilzen Formation (strongly layered sands). The Rupel Group 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' ...

Tongeren Group The Tongeren Group is a lithostratigraphic unit (a sequence of rock strata) in the subsurface of Belgium. It consists of shallow marine, epicontinental and/or continental clays and sands from the late Eocene to early Oligocene epochs (between ...

(

Sint Huibrechts-Hern Formation ''Sint'' (released on DVD as ''Saint'' in Europe and ''Saint Nick'' in the United States) is a 2010 Dutch dark comedy horror film about Sinterklaas, the character on which the Anglo-Saxon Santa Claus is based. The film was directed by Dick Maa ...

Zelzate Formation Zelzate () is a municipality located in the Belgian province of East Flanders. The municipality only comprises the town of Zelzate proper. In 2021, Zelzate had a total population of 13,124. The total area is 13.71 km2. Zelzate is divided int ...

) or

Maldegem Formation The Maldegem Formation ( nl, Formatie van Maldegem; old name: Kallo Complex) is a geologic formation in the Belgian subsurface. The formation consists of alternating marine clay and sand strata, deposited during the late Eocene. The Maldegem For ...

. The group can be covered by a range of younger formations, such as the late Oligocene

Voort Formation The Voort Formation or Voort Member ( nl, Formatie van Voort or ; abbreviation in Belgium: Vo or in the Netherlands: VEVO) is a stratigraphic unit in the subsurface of north Belgium and the south of the Netherlands. The unit has the status of a f ...

, the

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...

Berchem Formation Berchem () is a southern district of the municipality and city of Antwerp in the Flemish Region of Belgium. Berchem is located along the old ''Grote Steenweg'' (Dutch for 'Big Paved Road') that has connected Brussels to Antwerp for several centu ...

Bolderberg Formation Heusden-Zolder (; li, Heuze-Zolder ) is a municipality located in the Belgian province of Limburg near Hasselt. On 1 January 2006 Heusden-Zolder had a total population of 30,769. The total area is 53.23 km² which gives a population densit ...

or the

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Kattendijk Formation The Kattendijk Formation (also known as the Kattendijk Sands) is a five million years old marine geological formation north of Antwerp, Belgium. including the north-western parts of the Campine region. The area was named by De Heuter and Laga in 1 ...

References

*; 1849: ''Rapport sur la Carte géologique du Royaume'', Bulletin de l'Académie royale de Belgique 16 (2^ième partie), p. 370 () * (eds.); 2001: ''Paleogene and Neogene lithostratigraphic units (Belgium)'', Geologica Belgica 4(1-2), p. 135-152 Geologic groups of Europe Geologic formations of Belgium Lithostratigraphy of Belgium Oligocene {{Europe-geologic-formation-stub