Skip directly to content

Asdonk Member

(approved 02/2011)

Authors: Dusar, M. & Lagrou, D.

Name: Derived from Asdonk (Leopoldsburg), location of borehole KS37.

Stratotype: Borehole KS37, GeoDoc 047W0267, DOV: kb17d47w-B264; Lambert coordinates x = 210829, y = 202989, z (ground level) = 44 m; depth interval: 754 - 771,5 m. Stratotype selected because of representative geophysical well logs and good quality cuttings which were used for ecozonation (Figure 2).

Description: Gray green fine grained clayey sand (cuttings).

Green glauconite-rich calcareous fossiliferous clay and sand, occasionally more lithified by carbonate cement resulting in an alternation between indurated calcareous sandstone and loose sand layers; overall much less consolidated than the overlying Sonnisheide Member.

The Asdonk Member shows some lateral change. In the eastern coal mining district close to the Rur Valley Graben from which the detrital sediments are sourced, it consists of coarse grained sands reworked from the underlying Aachen Formation or Triassic Buntsandstein; indurated carbonate banks are present. A basal gravel may be present. In the western coal mining district it consists of green glauconitic clayey silt and fine sand, overlying a clay-rich base. This sequence thus is characterised by an upward increase of sand and carbonate content. In the Antwerp Campine, this sequence becomes a clayey marl not unlike the smectite facies in the Hallembaye section (Meuse valley).

Underlying strata: Carboniferous to Permo-Triassic basement or Aachen Formation. If the Vaals Formation is directly resting on the Carbonifeous coal measures group, the contact is rather clear-cut under a thin weathering zone on average 2 m thick with open cracks filled with marl. The more to the south, the cleaner, and more strongly eroded the unconformity surface will be. If the Vaals Formation is overlying the Aachen Formation and/or Triassic Buntsandstein, the unconformity is more irregular, presenting indications for ravination. Underlying strata are more strongly weathered resulting in decomposition of the rocky fabric.

Overlying strata: Sonnisheide Member, upper part of the Vaals Formation, with sharp transition.

Area: Campine basin, with exception of its western margin, corresponding to the subcrop area of Vaals Formation.

Thickness: From 754 m to 771,5 m (17,5 m) in the stratotype KS37, delineated by geophysical well logs. Thickness variation is greater than for the overlying Sonnisheide Member, exceeding 50 m in the eastern Campine and between 11 and 40 m in the western Campine.

Age: early Campanian

Dinoflagellate zone A, based on samples Turnhout 987 m and Hallembaye, Smectite de Herve (Slimani, 2000).

Ecozonation Felder 2001: Ib


DUSAR, M. & LAGROU, D., 2007. Cretaceous flooding of the Brabant Massif and the lithostratigraphic characteristics of its chalk cover in northern Belgium. Geologica Belgica, 10/1-2: 27-38.

FELDER, P.J., 2001. Bioklasten-stratigrafie of ecozonatie voor het krijt (Santoniaan - Campaniaan - Maastrichtiaan) van Zuid-Limburg en oostelijk België. Memoirs of the Geological Survey of Belgium 47: 141 p.

FELDER, W.M. & BOSCH, P.W., 2000. Geologie van Nederland deel 5: Krijt van Zuid-Limburg. Nederlands Instituut voor Toegepaste Geowetenschappen, 192 p.

LAENEN B., 2002. Lithostratigrafie van het pre-Tertiair in Vlaanderen. Studie uitgevoerd i.o.v. Vlaamse Overheid, LNE-ALBON. Vito-rapport 2002/ETE/R/063.

LAGROU D. & DREESEN R., i.s.m. DUSAR M., 2005. Kartering en karakterisering (sedimentpetrografisch en petrofysisch) van de krijtgesteenten in Vlaanderen. Onderzoek i.o.v. Vlaamse Overheid LNE-ALBON, Viot-rapport 2005/MAT/R/0256, 104 p. + bijlagen.

MATTHIJS J. & LAGROU D., in preparation. Opbouw van een geologisch 3D-lagenmodel: De lithostratigrafische indeling van de afzettingen uit het Krijt. VITO-rapport,.Studie i.o.v. Vlaamse Overheid, LNE-ALBON,

ROBASZYNSKI F., DHONDT A. & JAGT J.W.M., 2001. Cretaceous lithostratigraphic units (Belgium) in Bultynck P. & Dejonghe L. (Eds.) Guide to a revised lithostratigraphic scale of Belgium, Geologica Belgica 4/1-2: 121-134.

STAINIER, X., 1925. Le bassin houiller du Nord de la Belgique. Situation au 31 décembre 1924. Annexe: Sondage n° 91 (Houthaelen-Meulenberg). Annales des Mines de Belgique 26: 139-172.

SLIMANI, H., 2000. Nouvelle zonation aux kystes de dinoflagellés du Campanien au Danien dans le nord et l'est de la Belgique et dans le sud-est des Pays Bas. Memoirs of the Geological Survey of Belgium 46 : 87 p.