The information on this page is a summary description.
The full formal description is available here: Veldhoven Formation
Abbreviation
Vd
Parent unit
Child units
Voort Member, Wintelre Member, Someren Member
Lithological description
The Veldhoven Formation consists of fine grained glauconitic mollusc-bearing sand (Voort and Someren members) containing in some locations rich mollusc beds near its base (Voort Member in Campine coalfield) and with a clay unit in its middle part (Wintelre Member). Other clayey intercalations can occur in the sand.
Age
Van Simaeys (2004) and De Man et al. (2010) have described two gravel layers in the Veldhoven Formation from Weelde and Mol-1 boreholes in the Antwerp Campine, which subdivide the Chattian deposits in three parts corresponding to changes in the dinoflagellate cyst zonation. They are parallel to the boundaries between dinocyst zones NSO-6 – NSO-7 and NSO-7 – NSO-8 respectively. Munsterman & Deckers (2020) confirmed the presence of Aquitanian sediments above the Chattian sediments, underneath the black sand of the Berchem Formation (equivalent to the Groote Heide Formation in the Netherlands) in the Weelde borehole, suggesting that residual deposits of the same age as the Wintelre or Someren members are occurring outside the graben. There exists a discrepancy in interpretation between the former and the latter authors. Munsterman & Deckers (2020) place the Veldhoven (named Voort) – Berchem Formation boundary below the gravel layers in the Weelde borehole, which Van Simaeys (2004) and De Man et al. (2010) consider as a intra-Chattian boundary, in line with the Chattian as described in Hager et al. (1998).
Thickness
The thickness is 295 m in borehole Molenbeersel, in the Roer Valley Graben where the Veldhoven Formation is fully developed. Outside the graben the Veldhoven Formation is gradually wedging out.
Area of occurrence
The Veldhoven Formation is the youngest of the Paleogene stratigraphic units in Belgium, but it is also the first formation whose depositional area and thickness is controlled by active subsidence of the Roer Valley Graben. Hence, the Veldhoven Formation is subcropping in the Roer Valley Graben and adjoining part of the Campine Basin. As this formation is only accessible from boreholes, initial information came from the Campine coal mining district. There, only the lower part of the formation is encountered, named Voort Sand, after the locality name where the shafts of colliery Zolder were sunk (Van Straelen, 1923). This became the original type section of the Voort Formation, but is now considered as the type section for the Voort Member of the Veldhoven Formation.
Type locality
Belgian parastratotype borehole Molenbeersel, drilled 1988 till final depth of 1773 m; GeoDoc 049W0226, ground level +33 m; Lambert coordinates x 247660, y 207752, Voort Formation 680 – 975 m below ground level.
Someren Member 680-774 m S&T 2 to 4
Wintelre, ex-Veldhoven Member 774-840 m S&T 1
Voort Member above gamma-ray peak 840-920 m S&T 07 to 09
Voort Member gamma-ray peak interval 920-940 m S&T 06
Voort Member below gamma-ray peak 940-975 m S&T 05
Lithostratigraphic subdivision of the Veldhoven Formation in the Molenbeersel borehole, with depth range and corresponding Schneider and Thiele (1965) hydrostratigraphic codes of the Lower Rhine Basin and Chattian age assignments based on correlation with type sections in the Lower Rhine coal and salt districts. Table 1 in Dusar & Vandenberghe, 2020 (cf. Matthijs et al., 2016).
Alternative names
Voort Formation. Former Veldhoven Member is renamed to Wintelre Member.
Authors
Dusar, M. & Vandenberghe, N.
Date
01/09/2023
Cite as
Dusar, M. & Vandenberghe, N., 2023. The Veldhoven Formation, 01/09/2023. National Commission for Stratigraphy Belgium. http://ncs.naturalsciences.be/lithostratigraphy/Veldhoven-Formation
