Vaals Formation - VAA
Vaals Formation - VAA
Authors: Netherlands Geological Survey (1957), W.M. Felder (1975).
Description: In the type area, the unit comprises six members with a total thickness of about 150 m, to which W.M. Felder & Bosch (2000) added a seventh, the Benzenrade Member.
- Raren Member (thickness between 12 and 18 m): predominantly laminated, yellow to greyish-green, glauconitic fine-grained sands, in channel fills. In places lenticular sandstone bodies occur with rich faunas, interfingering in westerly direction with silty fine-grained sands and sandy silts.
- Cottessen Member (thickness up to 10 m): cyclic alternation of yellow to greyish-green, glauconitic laminated channel fills, and light grey-brown, fine-grained sandy silts to silty fine-grained sands. Occurring locally are fossil-rich sandstone banks; towards the west, a facies change similar to that in the Raren Member occurs. The top corresponds to a fossiliferous, dark grey-green glauconitic horizon.
- Gemmenich Member (thickness about 10-12 m): similar to Cottessen Member.
- Vaalsbroek Member (thickness 4-6 m): cyclic alternation of yellow to greenish-grey, glauconitic, laminated fine-grained sands without silt, and glauconitic, silty, fine sands with extensive bioturbation.
- Beusdal Member (thickness between 14 and 25 m); cyclic alternation of poorly indurated, yellow to greyish-green, glauconitic laminated fine sands without silt and glauconitic, silty, fine-grained sands with extensive bioturbation.
- Terstraten Member (thickness up to about 15 m): greyish-green, silty fine-grained sandy silts with glauconite. Base characterised by poorly indurated, light grey, fine-grained sandy silt with fossil hash, in particular the bivalve Cucullaea subglabra.
- Benzenrade Member: see W.M. Felder & Bosch (2000)
Stratotypes:
-Raren Member: road cutting along Sandbergweg, Aachen-Vaalserquartier, Germany (co-ordinates 308.700/200.600).
-Cottessen Member: road cutting along Holle Weg at Cottessen (Limburg, the Netherlands) (co-ordinates 308.200/194.540).
-Gemmenich Member: road cutting between Terstraten and grenspaal 7, Bleiberg (Plombières), Liège province (Dutch co-ordinates 196.120/307.300).
-Vaalsbroek Member: road cutting at Mechelen-Overgeul (Limburg, the Netherlands) (co-ordinates 311.820/192.200).
-Beusdaal Member: road cutting between Sippenaeken and Teuven, Liège province (Dutch co-ordinates 306.830/192.240).
-Terstraten Member: road cutting east of Terstraten on the Belgian-Dutch border, near grenspaal 6) (co-ordinates 307.420/196.420).
-Benzenrade Member: outcrop at Den Dael on the Putberg between Benzenrade and Ubachsberg (Limburg, the Netherlands) (co-ordinates 195.800/318.820).
Area: Type area in direct vicinity of the Vaalserberg, southeast of Vaals (Limburg, The Netherlands)
Thickness: Total thickness up to about 150 m.
Age: Early Early Campanian to early Late Campanian by ammonoid and coleoid cephalopods: Belemnitella praecursor, Bt. m. mucronata, Gonioteuthis granulataquadrata, G. q. quadrata, Scaphites hippocrepis II-III, Trachyscaphites spiniger, Pachydiscus duelmensis, P. launayi, Eupachydiscus levyi, Hoplitoplacenticeras marroti, H. cf. coesfeldiense, Glyptoxoceras vaalsiense, andBaculites vaalsensis.
Remarks: - Formerly described as "Smectite de Herve" (Dumont,1832) , "Système hervien"(Dumont, 1850) "Assise de Herve" [Rutot (1894), Leriche (1929), Marlière (1954)], "Vaalser Groenzand" or Hervian (Netherlands Geological Survey, 1957).
- Recent references: Albers (1976), Albers & Felder (1979), Jagt (1989), Kennedy & Jagt (1995, 1998), Jagt (1999), Felder & Bosch (2000).
Complementary data (M. Dusar, 2011)
The Vaals Formation is occurring in the Belgian - Dutch - German boundary area and the eastern Pays de Herve, mostly in the form of greensand. Further to the west, the Vaals Formation is often completely eroded by channels filled with chalks belonging to the Gulpen Formation or may consist of bluish weathering clays as in the Hallembaye quarry north of Visé, displayint the so-called 'Smectite de Herve' facies. On the eastern part of the Brabant Massif, the Vaals Formation is represented by patches of coarse residual deposits. The Vaals Formation is more extensively developed in the Campine Basin, where the lithostratigraphic subdivision of the type area cannot be distinguished. Instead, a two-fold subdivision has been made, which further west at the western margin of the Campine basin and on the Brabant Massif evolves into the chalks of the Nevele Formation. This new subdivision of the Vaals Formation is described in more detail on this website.
Also, the Benzenrade Member, added to the Vaals Formation by Felder & Bosch (2000) in the area between the type area and the southern margin of the Roer Valley Graben, is considered as a separate unit, laterally equivalent of the Gulpen Formation, the new Dorne Formation (see separate description on this website).
version June 7, 2010
Lagrou David, Dusar Michiel
Vaals Formation (after Robaszynski et al., 2001)
Name : Derived from Vaals, commune in Netherlands South Limburg
Stratotype: The Vaals Formation comprises 6 Members whose stratotypes are located in the Belgian - Dutch - German border area, to which Felder & Bosch (2000) added a seventh, the Benzenrade Member, replacing the entire Gulpen Formation in the fault block area close to the Rur Valley Graben.
Description: Greensand facies (glauconitic sands) in the type area.
Underlying strata: Aachen Formation in type area, unconformably overlying Triassic or Carboniferous strata in Campine and eastern Hesbaye where Aachen Formation is absent.
Overlying strata: Gulpen Formation or Kunrade facies, equivalent to topmost Gulpen and/or lower Maastricht Formation in the Rur Valley Graben shoulder north of Vaals.
Area: The Cretaceous basin to the east and northeast of the Brabant Massif including the outcrop zone near the stratotype (region Vaals - Aachen - Raeren) extending over the Pays de Herve into the Basse Meuse (Hallembaye quarry) and the subcrop zone in the Campine Basin. The formation is absent north of the Dilsen Fault, approaching the Rur Valley Graben and wedges out towards the Brabant Massif. In the Antwerp Campine lateral facies changes turn greensand into chalk. The western edge of the Campine is already fully developed in chalk facies, assigned to the Nevele Formation (Dusar & Lagrou, 2007).
Thickness: 150 m in stratotype area; between 30 m and 90 m in Campine, reduced to 20 m in eastern Hesbaye (Meuse valley).
Age: Early Early Campanian to early Late Campanian.
Comments: The Vaals Formation corresponding to its initial description with subdivision in its 6 classical members is easily distinguished from under- or overlying strata by its greenish colour, sandy texture and absence of gravels (with the possible exception of a basal gravel). Lithological characteristics and sequence development are much more regular than the overlying Gulpen or underlying Aachen formations in the Campine basin. Even so, its sand content and grainsize are higher in the eastern Campine, closer to the Rur Valley Graben.
The subdivision in 7 members is representative only for the stratotype area in the eastern part of the Cretaceous basin and cannot be recognised in the Campine Basin. Here, the Vaals Formation can clearly be subdivided in 2 units, with the exception of the border area to the Rur Valley Graben, composed of a reduced thickness of coarse reworked sands. Along the western edge of the Campine Basin, the chalky Nevele Formation contains a lower unit resulting from a gradual lateral transition from greensand into chalk. However, the lateral equivalent of the Vaals Formation within the Nevele Formation is still marked by a slight clay-shift on geophysical well logs (provisionally named the Wachtebeke Member).
Detailed mapping at the level of members in the Campine basin, including the twofold subdivision of the Vaals Formation has created the need for a formal subdivision of the Vaals Formation in two new members (Lagrou & Dreesen, 2005; Matthijs & Lagrou, in preparation). Data supporting this twofold subdivision come from geophysical well logs (coal, geothermal energy and gas storage exploration wells drilled since the 1980's) and cores (coal exploration boreholes and mining shafts drilled between 1908 and 1924, and borehole Turnhout). Borehole Houthalen Meulenberg, GeoDoc 62E0223 is considered most representative for the cored sections (Stainier, 1925).
Sonnisheide Member (new)
Name: Derived from Sonnisheide in Houthalen-Helchteren, location of borehole KS29.
Stratotype: Borehole KS29, GeoDoc 062E0280; DOV kb25d62e-B284, Lambert coordinates x = 224190, y = 194595, z (ground level) = 80 m; depth interval: 568 - 633 m. Stratotype selected because of representative geophysical well logs and good quality cuttings which were used for ecozonation (Figure 1).
Description: Greenish grey lightly silty marl (cuttings).
In the many (partially) cored sections from coal exploration boreholes, this member is clearly distinguished and described as glauconite-bearing grey marl, often bioturbated with Gyrolithes (typical for Herve Smectite) and other ichnofossils, transported molluscs, occasional indurated limestone beds; richer in glauconite and more coarse-grained towards the base, seldomwith basal gravel bed.
The Sonnisheide member is rather homogeneous, with average carbonate content of 50%, remaining more sandy in the east and more silty-marly in the west. It consists of glauconitic marls with fine sands or silts. This sequence displays a slight upward increase in clay and carbonate content (Laenen, 2002).
Underlying strata: Asdonk Member, lower part of the Vaals Formation
Overlying strata: white chalk ('Schreibkreide') of the Zeven Wegen Member, lowest member of the Gulpen Formation. Contact by hardground.
Area: Campine basin, with exception of its western margin, corresponding to the subcrop area of Vaals Formation
Thickness: From 568 m to 633 m (65 m) in the stratotype KS29, delineated by geophysical well logs. Generally somewhat thinner, around 30 m in thickness. Thickness variation is in line with general up and down trends for the entire Cretaceous section, indicative for the influence of the Rur valley Graben inversion.
Age: early to late Campanian.
Dinoflagellate Xenascus wetzelii Zone, Exochosphaeridium? Masurii Subzone, Zonule a (Slimani, 2000) present in borehole Turnhout but not in Hallembaye quarry.
Ecozonation Felder 2001: IIa, Id & Ic.
Asdonk Member (new)
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
References:
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.
