Kotter Member KNNSK

 

Premise Member defined by van Adrichem Boogaert & Kouwe (1993).
Derivatio nominis Named after the Kotter oil field, located in the Broad Fourteens Basin (block K18a).
Type section Location map See figure (pdf)
  Well K18-02-A (pdf)
  Location N 53°05’12.0
E 03°57’54.4
  Depth 1743 to 1905 m
  Length 162 m along hole
  Reference .
Additional section Location map See figure (pdf)
  Well K18-03 (pdf)
  Location N 53°05’54.2
E 03°58’29.0
  Depth 1801 to 1859 m
  Length 58 m along hole
  Well K18-05 (pdf)
  Location N 53°01’23.6
E 03°57’42.5
  Depth 1962 to 2074 m
  Length 112 m along hole
  Depth 2100 to 2150 m
  Length 50 m along hole
Definition Massive sequence of fine- to medium-grained, locally coarse-grained sandstones, generally light-grey, well-sorted with sub-angular to rounded grains, moderately cemented, both bioturbated and stratified. The sandstones locally contain streaks of heavy mineral sand, coal laminae and pyrite particles.
Upper Boundary In the north-west, the Kotter Member is conformably overlain by the Vlieland Claystone Formation. The Helm Member of the Breeveertien Formation (Delfland Subgroup) is a marginally marine, fine-grained equivalent to the east and south.
Lower Boundary The Kotter Member stratigraphically rests slightly unconformably on the Breeveertien Formation (Late Kimmerian II pulse), which also forms its lateral equivalent to the south and east.
Distribution The occurrence of the Kotter Member is restricted to the Broad Fourteens Basin and is developed only along the central axis of this basin. The thickest development is seen in K18. In well K18-05 the Kotter Member interfingers with this Helm Member To the north(-west) the member grades into the Vlieland Claystone Formation.
Age A latest Ryazanian to Early/mid-Valanginian age is inferred from biostratigraphical data (mainly palynomorphs) and stratigraphic position. Characteristic dinoflagellate forms are Muderongia simpex microperforata, M. extensiva, Canningia compta, Lagenorhytis deliculata, Pseu-doceratium ’eopelliferum’, and Gochteodinia villosa (Eg-montodinium torynum to Endoscrinium pharo dinoflagellate (sub-)zone).
Depositional Setting The sandstones were deposited as barrier sands. The main facies recognised in cores include: - fine-grained lower-shoreface sands characterised by bioturbation and faint stratifications, - medium- to coarse-grained upper-shoreface sands with subhorizontal to trough cross-bedding and occasional bioturbation, - foreshore facies with horizontal to low-angle bedding and coal beds interpreted to have resulted from storm deposition.
Sequence Stratigraphy Sequence LZB 2.1 (early). Internally two subsequences can be recognised. In well K18-05 sandstones belonging to both subsequence Highstand systems tracts were found.
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].