Sleen Formation ATRT

 

Premise Definition after NAM and RGD (1980) . The lithological affix has been dropped.
Derivatio nominis Named after the municipality of Sleen, which is situated in the southeastern part of the Dutch province of Drenthe.
Type section Location map See figure (pdf)
  Well K14-01 (pdf)
  Location N 53°17’15.2
E 03°37’07.3
  Depth 1604 to 1623 m
  Length 19 m along hole
  Reference NAM and RGD (1980)
Additional section Location map See figure (pdf)
  Well Werkendam-2 (pdf)
  Location N 51°47’29.7
E 04°50’22.1
  Depth 2803 to 2838 m
  Length 35 m along hole
Definition Sequence of grey, fossiliferous, claystones, overlain by brown, locally sandy claystones (often containing a considerable quantity of megaspores). Generally, the Sleen Formation is easily recognisable on wire-line logs by its uniform thickness, relatively high gamma-ray and low acoustic velocity readings.
Upper Boundary .The unit lies below the basal argillaceous limestone of overlying the Aalburg Formation.
Lower Boundary The unit usually lies on top of the reddish anhydritic mudstone beds of the Keuper Formation (Upper Germanic Trias Group). In the eastern part of the Netherlands the formation locally rests unconformably upon older members of the Keuper Formation or the light-greenish/grey carbonates and marls of the Muschelkalk Formation or Röt Formation.
Distribution The distribution of the unit coincides with that of the entire Altena Group.
Age The formation generally yields rich palynofloras and microfaunas of Rhaetian age.
Depositional Setting The abundancy and types of fossils encountered in this formation indicates deposition in a shallow, open-marine environment. The uniform thickness is evidence of a period of very gentle, uniform subsidence.
References See References Lower and Middle Jurassic

Van Adrichem Boogaert, H.A. & Kouwe, W.F.P., 1993-1997. [Stratigraphic unit]. In: Stratigraphic Nomenclature of the Netherlands.
Retrieved [Datum] from [url].