Weiteveen Formation SKWF


Premise Definition extended after NAM and RGD (1980) . Equivalent of the M√ľnder Mergel Folge and Serpulit in Germany (Schott (1951) ; t Hart (1969) ).
Derivatio nominis Named after the village of Weiteveen, municipality of Schoonebeek, in the southeastern part of the province of Drente.
Type section Location map See figure (pdf)
  Well Schoonebeek-197 (pdf)
  Location N 52°38’58.0
E 07°02’34.2
  Depth 1230 to 1590 m
  Length 360 m along hole
  Reference NAM and RGD (1980)
Additional section Location map See figure (pdf)
  Well Ruinen-1 (pdf)
  Location N 52°44’09.8
E 06°27’12.8
  Depth 1046 to 1196 m
  Length 150 m along hole
  Well Exloo Odoorn-2 (pdf)
  Location N 52°54’20.7
E 06°51’57.8
  Depth 1697 to 1718 m
  Length 21 m along hole
  Well De Bente-1 (pdf)
  Location N 52°41’37.8
E 06°46’15.7
  Depth 1174 to 1344 m
  Length 170 m along hole
  Well Oldenzaal-2 (pdf)
  Location N 52°17’18.8
E 06°56’23.8
  Depth 295 to 588 m
  Length 293 m along hole
Definition The lithology of the formation depends on position in the basin. When its thickness is reduced (i.e. laid down on swells), it consists of basal, generally coarse-sandy to conglomeratic clastics, followed by light- to dark-grey, anhydritic, marly claystones with limestone intercalations. In the basin intercalated halite beds occur. Further towards the western and northern margins of the Lower Saxony Basin, the basal clastics loose their prominent character, while the evaporite intercalations shale out. Shell microcoquina laminae and beds are frequently observed.
Upper Boundary The upper boundary, with the Coevorden Formation, is marked by a characteristic wire-line log marker, corresponding to a conspicuous clay-stone break in a clayey-marly interval with fossiliferous limestones (top Serpulite Member).
Lower Boundary The formation unconformably overlies the Altena Group or older sediments.
Distribution Dutch part of the Lower Saxony Basin, which reaches the easternmost parts of the Dutch provinces of Groningen, Drente and Overijssel. Over Zechstein salt swells the formation can be thinner or absent.
Age Kimmeridgian - Late Portlandian (t Hart (1969) , Kemper (1973) Kemper (1973) ). The base of the Ryazanian (Cretaceous) is currently placed in the uppermost parts of the Serpulite Member Allen and Wimbledon, W.A (1991) . The end of the Portlandian is characterised by a sharp decrease in Classopollis abundance Herngreen et al (1980) . An ostracod zonation is frequently used for regional correlation (Wolburg (1949) ; Sung (1955) ).
Depositional Setting Restricted lacustrine basin-margin to marginal-marine sub-basin (lagoonal) setting, grading into a floodplain to fluvial-plain setting along the extreme basin-fringe. An estuarine basin circulation favoured the periodic formation of evaporites. Lithofacies tend to shift laterally in time, but the associations can be grouped into palaeo-geographically controlled facies belts (Schott (1951) , t Hart (1969) ).
Sequence Stratigraphy The formation represents several full sequences (LZA 4.6 - LZB 1.5a). Evaporitic members and beds reflect Low-stand systems tracts, while shaly/marly members and beds indicate Transgressive to Early Highstand systems tracts. Shoaling sequences, as seen in the Serpulite Member, reflect Highstand systems tracts.
  In the type area the formation is subdivided into six members:
  SK Niedersachsen Group
  SKWF Weiteveen Formation
  SKWFF Serpulite Member
  SKWFE Weiteveen Upper Marl Member
  SKWFD Weiteveen Upper Evaporite Member
  SKWFC Weiteveen Lower Marl Member
  SKWFB Weiteveen Lower Evaporite Member
  SKWFA Weiteveen Basal Clastic Member
  This subdivision into members is only applicable in the immediate surroundings of the type well. Away from the type section, the formation thins rapidly to the north and west, to show a fairly constant thickness throughout the rest of the Dutch Lower Saxony Basin. The individual units can be correlated across to the northern margin of the basin, although they have severely changed in character. In more marginal settings, the four members between the Serpulite Member and the Weiteveen Basal Clastic Member can be lumped into a Main Weiteveen member (SKWFM), which is not defined separately here.
References See References Upper Jurassic/ Lower Cretaceous

Van Adrichem Boogaert, H.A. & Kouwe, W.F.P., 1993-1997. [Stratigraphic unit]. In: Stratigraphic Nomenclature of the Netherlands.
Retrieved [Datum] from [url].