Upper Coevorden Member SKCFU

 

Premise Definition extended after NAM and RGD (1980) , originally Upper Coevorden Clay Member The lithological affix has been deleted. Equates with the Osterwald Folge of Kemper (1973).
Derivatio nominis Named after the town of Coevorden in the southeastern part of the Dutch 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 944 to 1041 m
  Length 97 m along hole
  Reference NAM and RGD (1980)
Additional section Location map See figure (pdf)
  Well Exloo Odoorn-2 (pdf)
  Location N 52°54’20.7
E 06°51’57.8
  Depth 1644 to 1653 m
  Length 9 m along hole
Definition Section of brownish-grey, occasionally fine-sandy claystones, which are typically much less calcareous than the Middle Coevorden Member t Hart (1969) . Locally highly bituminous, with paper-thin lamination.
Upper Boundary The formation is intercalated between the silty marl/limestone succession of the Middle Coevorden Member and the basal, generally glauconitic beds of the Rijnland Group.
Lower Boundary The boundary with the Middle Coevorden Member is marked by an upward drop in resistivity-log readings.
Distribution Dutch part of the Lower Saxony Basin, which covers the easternmost parts of the Dutch provinces of Groningen, Drente and Overijssel. The member has often been removed by later erosion (De Bente-1, Ruinen-1, Oldenzaal-2).
Age Ryazanian - earliest Valanginian. In the local ostracod zonation the member covers Wealden 5 - 6 (Wolburg (1949) , Sung (1955) ). Wealden 5 and 6 often are placed in the earliest Valan-ginian (e.g. Allen, P. and Wimbledon, W.A (1991) ), but this has not yet been widely accepted.
Depositional Setting Lagoonal to fresh-water lake setting with repeated marine influences. Fines settled from suspension. Limestone (lumachelle/microcoquina) beds are interpreted as storm deposits or hardgrounds.
Sequence Stratigraphy Interpreted as the late Highstand systems tract of Haq (1988) ’s sequence LZB 1.6, locally possibly reaching up into the early Transgressive systems tract of sequence LZB 2.1.
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].