Middle Graben Sandstone Member SLCMS

 

Premise The Middle Graben Sandstone Member, defined by Herngreen & Wong (1989), is part of the Middle Graben Formation (fig. 6 in Munsterman et al., 2012).  
Derivatio nominis Named after the Central Graben.
Type section Location map See figure (pdf)
  Well F05-01 (pdf)
  Location N 54°47’10.7
E 04°29’14.6
  Depth 2628 to 2648 m
  Length 20 m along hole
  Reference NAM and RGD (1980)
Definition Sections of yellow fine-medium, moderately sorted sandstone with calcareous cement. The sands are often characterised by one or two coal beds, showing a spiky character on the GR-log. The sandy bodies have a distinct coarsening upward trend. In a few areas (F03-FB Field) a double sand body is present, both parts with a coarsening upward trend.
Upper Boundary Top of this member is characterised by distinct (Gamma Ray, Int. transit time & Resistivity) log breaks defining the contact with the overlying non-calcareous claystones of the Middle Graben Formation.
Lower Boundary Base of this member is characterised by distinct (Gamma Ray, Int. transit time & Resistivity) log breaks defining the contact with the underlying non-calcareous claystones of the Middle Graben Formation.
Distribution Restricted to the northern Dutch Central Graben, Blocks F02, F03, F05 and F06 (see pdf).
Age Sequence 1 sensu Abbink et al. (2006): Early-Middle Oxfordian. Characteristic palynomorphs are Contignisporites type 13/28 (FOD: M. Oxfordian), Striatella spp., Precicatricosisporites inae, P. irregularis and Neoraistrickia gristhorpensis (LOD: E. Oxfordian).
Depositional Setting Local prograding lake delta fill complexes.
References See References Upper Jurassic/ Lower Cretaceous
D.K. Munsterman, R.M.C.H. Verreussel, H.F. Mijnlieff, N. Witmans, S. Kerstholt-Boegehold & O.A, Abbink (2012), Revision and update of the Callovian-Ryazanian Stratigraphic Nomenclature in the northern Dutch Offshore, i.e. Central Graben Subgroup and Scruff Group. Netherlands Journal of Geosciences-Geologie en Mijnbouw, 91 (4):555-590.
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