Rupel Group
Encyclopedia
The Rupel Group is a stratigraphic group
of rock strata
in the subsurface
of Belgium
. It is subdivided into three formations that are all marine
deposits (sands and clays) of Oligocene
age.
age (34 to 28 million years ago) of the geological timescale. Both group and age are named after the Belgian river Rupel
. The Rupel Group corresponds with the Rupel Formation
in the Netherlands
.
fine sand, containing fossils), the Boom Formation (a thick clay deposit, containing loam
layers and septaria) and the Eigenbilzen Formation (strongly layered sands).
The Rupel Group lies stratigraphically on top of the late Eocene
Tongeren Group
(Sint Huibrechts-Hern Formation or Zelzate Formation) or Maldegem Formation
. The group can be covered by a range of younger formations, such as the late Oligocene Voort Formation
, the Miocene
Berchem Formation or Bolderberg Formation or the Pliocene
Kattendijk Formation.
Group (stratigraphy)
A group in stratigraphy is a lithostratigraphic unit, a part of the geologic record or rock column that consists of defined rock strata. Groups are divided into formations and are sometimes themselves grouped into "supergroups"....
of rock strata
Stratum
In geology and related fields, a stratum is a layer of sedimentary rock or soil with internally consistent characteristics that distinguish it from other layers...
in the subsurface
Subsurface
Subsurface is the seventh studio album by British progressive metal band Threshold. The album was released in August 2004, and received an Album of the Month award in several European music magazines....
of Belgium
Belgium
Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...
. It is subdivided into three formations that are all marine
Marine (ocean)
Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...
deposits (sands and clays) of Oligocene
Oligocene
The Oligocene is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present . As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...
age.
Name
The Rupel Group was first named by Belgian geologist André Hubert Dumont in 1849. It shares its name with the RupelianRupelian
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 and . It is preceded by the Priabonian stage and is followed by the Chattian stage....
age (34 to 28 million years ago) of the geological timescale. Both group and age are named after the Belgian river Rupel
Rupel
The Rupel is a tidal river in northern Belgium, right tributary of the Scheldt. It is about 12 km long. It flows through the Belgian province Antwerp. It is formed by the confluence of the rivers Dijle and Nete, in Rumst. It flows into the Scheldt at Rupelmonde. Towns along the Rupel are...
. The Rupel Group corresponds with the Rupel Formation
Rupel Formation
The Rupel Formation is a geologic formation in the subsurface of the Netherlands that consists of Oligocene marine sands and clays. The Rupel Formation is part of the Middle North Sea Group and correlates exactly with the Belgian Rupel Group....
in the Netherlands
Netherlands
The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...
.
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 glauconiferousGlauconite
Glauconite is an iron potassium phyllosilicate mineral of characteristic green color with very low weathering resistance and very friable.It crystallizes with a monoclinic geometry...
fine sand, containing fossils), the Boom Formation (a thick clay deposit, containing loam
Loam
Loam is soil composed of sand, silt, and clay in relatively even concentration . Loam soils generally contain more nutrients and humus than sandy soils, have better infiltration and drainage than silty soils, and are easier to till than clay soils...
layers and septaria) and the Eigenbilzen Formation (strongly layered sands).
The Rupel Group lies stratigraphically on top of the late Eocene
Eocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...
Tongeren Group
Tongeren Group
The Tongeren Group is a lithostratigraphic unit 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 .The Belgian Tongeren Group correlates with the Dutch Tongeren Formation...
(Sint Huibrechts-Hern Formation or Zelzate Formation) or Maldegem Formation
Maldegem Formation
The Maldegem Formation is a geologic formation in the Belgian subsurface. The formation consists of alternating marine clay and sand strata, deposited during the late Eocene....
. The group can be covered by a range of younger formations, such as the late Oligocene Voort Formation
Voort Formation
The Voort Formation or Voort Member is a stratigraphic unit in the subsurface of north Belgium and the south of the Netherlands. The unit has the status of a formation in Belgium but is seen as a member of the Veldhoven Formation in the Netherlands...
, the Miocene
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
Berchem Formation or Bolderberg Formation or the Pliocene
Pliocene
The Pliocene Epoch is the period in the geologic timescale that extends from 5.332 million to 2.588 million years before present. It is the second and youngest epoch of the Neogene Period in the Cenozoic Era. The Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch...
Kattendijk Formation.