Bentheim Sandstone Member KNNSP


Premise Definition extended after NAM and RGD (1980) . A new reference section is added which shows a thicker development.
Derivatio nominis Named after the town of Bad Bentheim in Germany.
Type section Location map See figure (pdf)
  Well Sleen Dommerskanaal-1 (pdf)
  Location N 52°41’39.7
E 06°52’49.8
  Depth 1555 to 1613 m
  Length 58 m along hole
Definition Generally fairly thick sequence of massive sandstones, calcareous, with abundant shell fragments, lignite particles and glauconite grains. Grain sizes predominantly range from fine to medium sand, but up to granule sizes occur. Gamma-ray logs often show one or more (stack-ed) funnel-shaped patterns. Rare clay beds are known. Bioturbation is common.
Upper Boundary The member is usually conformably under- and overlain by the Vlieland Claystone Formation (Bentheim Clay-stone Member, resp. Ruinen Member). In palaeogeographically elevated settings the Ruinen can also be absent, and the Bentheim Sandstone Member is covered unconformably by the Westerbork Member The lithological distinction between the two claystone members can be quite difficult, therefore biostratigraphy may aid differentiation. In salt-structure and basin-fringe-related settings the Bentheim Sandstone Member can be overlain unconformably by the Holland Formation or Lower North Sea
Lower Boundary .Locally, the Bentheim Claystone Member below is absent, bringing the Bentheim Sandstone Member in unconformable contact with the Coevorden Claystone Formation (Niedersachsen Group).
Distribution Dutch Lower Saxony Basin: eastern parts of the provinces Drente and Overijssel. Because of the definition, the distribution coincides with that of the Bentheim Claystone Member. The Friesland Member in the south of the Friesland Platform and Groningen High is its lateral equivalent to the north. The Bentheim Sandstone Member is restricted to the Lower Saxony Basin.
Age On the basis of correlation to well dated outcrops in Germany a late Early Valanginian age is inferred (Kemper, 1973a)
Depositional Setting Deposited in a coastal (deltaic) to marine (inner- to middle-neritic) setting, in prograding offshore-shoals and coastal-barrier systems. Sponge spicules and glauconite are considered indicative for an open-marine setting, whereas coarser clasts and lignitic matter point to a more proximal, coastal setting.
Sequence Stratigraphy The overall funnel-shaped GR-log pattern is indicative of Highstand systems tract of Haq (1988) ’s sequence LZB 2.1. The uppermost part may locally reflect LZB 2.2’s Transgressive systems tract.
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.
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