|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)|
|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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