The Voort Formation or Voort Member ( or ; abbreviation in

Belgium Belgium, officially the Kingdom of Belgium, is a country in Northwestern Europe. Situated in a coastal lowland region known as the Low Countries, it is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeas ...

: Vo or in the

Netherlands , Terminology of the Low Countries, informally Holland, is a country in Northwestern Europe, with Caribbean Netherlands, overseas territories in the Caribbean. It is the largest of the four constituent countries of the Kingdom of the Nether ...

: VEVO) is a

stratigraphic 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 ...

unit 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 north Belgium and the south of the Netherlands. The unit has the status of a

formation Formation may refer to: Linguistics * Back-formation, the process of creating a new lexeme by removing or affixes * Word formation, the creation of a new word by adding affixes Mathematics and science * Cave formation or speleothem, a secondary ...

in Belgium but is seen as a

member Member may refer to: * Military jury, referred to as "Members" in military jargon * Element (mathematics), an object that belongs to a mathematical set * In object-oriented programming, a member of a class ** Field (computer science), entries in ...

of the

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 ...

in the Netherlands. The Voort Formation consists of

shallow marine Shallow water marine environment refers to the neritic marine environment between the shore and the shelf break. This environment is characterized by oceanic, geological and biological conditions, as described below, and water in this environmen ...

sands with a 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 ...

age (

Chattian The Chattian is, in the geologic timescale, the younger of two ages or upper of two stages of the Oligocene Epoch/Series. It spans the time between . The Chattian is preceded by the Rupelian and is followed by the Aquitanian (the lowest stage ...

stage Stage, stages, or staging may refer to: Arts and media Acting * Stage (theatre), a space for the performance of theatrical productions * Theatre, a branch of the performing arts, often referred to as "the stage" * ''The Stage'', a weekly Brit ...

, about 25 million years old).

Stratigraphy

In Belgian

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 ...

the Voort Formation is part of the

Rupel Group 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. Name The Rupel Group was first named by Belgian geol ...

, though other formations in this group are slightly older (of the early Oligocene

Rupelian The Rupelian is, in the geologic timescale, the older of two age (geology), ages or the lower of two stage (stratigraphy), stages of the Oligocene epoch (geology), Epoch/series (stratigraphy), Series. It spans the time between . It is preceded b ...

stage). In the Netherlands the Voort Member is part of the Veldhoven Formation. In Belgium, a

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 ...

ey subunit is treated as a member of the Voort Formation (

Veldhoven Member Veldhoven () is a municipality and town on the Gender in the southern Netherlands, just southwest of Eindhoven, in the province of North Brabant. Topography Map of Veldhoven (town), Dec. 2013 Population centres The modern town of Veldhoven is ...

). In Dutch lithostratigraphy, this unit is classified as another member of the Veldhoven Formation and called the

Wintelre Member Wintelre is a village in the municipality of Eersel in the province of North Brabant, the Netherlands. Wintelre is part of the Acht Zaligheden (Eight Beatitudes), like Eersel, Duizel, Steensel, Knegsel, Netersel, Hulsel and Reusel. The village was ...

. In Belgium the Voort Formation is stratigraphically below the early

Miocene The Miocene ( ) is the first epoch (geology), 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 mea ...

marine

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 centur ...

(in

province of Antwerp Antwerp Province (; ; ; ), between 1815 and 1830 known as Central Brabant ( , , ), is the northernmost province both of the Flemish Region, also called Flanders, and of Belgium. It borders on the North Brabant province of the Netherlands to the ...

) or

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

(in

Limburg Limburg or Limbourg may refer to: Regions * Limburg (Belgium), a province since 1839 in the Flanders region of Belgium * Limburg (Netherlands), a province since 1839 in the south of the Netherlands * Diocese of Limburg, Roman Catholic Diocese in ...

). In the Netherlands it is below the early Miocene

Breda Formation The Breda Formation (; 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 the formation is not ve ...

. In Belgium the Voort Formation is on top of the older formations of the

(

Boom Formation Boom may refer to: Objects * Boom (containment), a temporary floating barrier used to contain an oil spill * Boom (navigational barrier), an obstacle used to control or block marine navigation * Boom (sailing), a sailboat part * Boom (windsurfin ...

or Eigenbilzen Formation), in the Netherlands the Voort Member is on top of the

Rupel Formation The Rupel Formation (abbreviation: RU) 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 Bel ...

Lithology

The Voort Formation consists of a 60 meters thick layer of greyish to greenish

mica Micas ( ) are a group of silicate minerals whose outstanding physical characteristic is that individual mica crystals can easily be split into fragile elastic plates. This characteristic is described as ''perfect basal cleavage''. Mica is co ...

ceous and glauconiferous fine sand. This is alternated by greenish sandy clay.

crag Crag may refer to: * Crag (climbing), a cliff or group of cliffs, in any location, which is or may be suitable for climbing * Crag (dice game), a dice game played with three dice * Crag, Arizona, US * Crag, West Virginia, US * Crag and tail, a ...

s or

pyrite The mineral pyrite ( ), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Fe S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral. Pyrite's metallic luster and pale brass-yellow hue ...

rich clay layers can occur locally. In the

Roer Valley Graben The Roer (, ) or Rur (; ) is a major river that flows through portions of Belgium, Germany and the Netherlands. It is a right (eastern) tributary to the Meuse (). About 90 percent of the river's course is in Germany. It is not to be conf ...

the formation can be up to 300 meter in thickness.

References

*Laga, P.; Louwye, S. & Geets, S. (eds.); 2001: ''Paleogene and Neogene lithostratigraphic units (Belgium)'', Geologica Belgica 4(1-2), p. 135-152

External links

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