Keuper Formation RNKP


Premise Formally introduced in the Netherlands by NAM and RGD (1980)
Derivatio nominis Name derived from the German stratigraphic nomenclature, where it is applied to the highest unit of the German Triassic.
Type section Location map See figure (pdf)
  Well L02-01 (pdf)
  Location N 53°57’14.0
E 04°30’47.0
  Depth 2808 to 3368 m
  Length 560 m along hole
Additional section Location map See figure (pdf)
  Well K14-01 (pdf)
  Location N 53°17’15.2
E 03°37’07.3
  Depth 1623 to 1810 m
  Length 187 m along hole
  Reference NAM and RGD (1980)
  Well Emmen-7 (pdf)
  Location N 52°46’56.6
E 06°50’37.4
  Depth 1610 to 1640 m
  Length 30 m along hole
Definition Sequence of red-brown to variegated, silty, anhydritic claystones with intercalated anhydrite, roch salt and subordinate sandstones.
Upper Boundary The Keuper Formation comprises the strata between the carbonates and marls of the Muschelkalk Formation.
Lower Boundary The base of the Keuper Formation is marked by a shift in the acoustic velocity, which is considerable lower in the Keuper Formation. Along the basin fringe the interval comprising the Red Keuper Claystone and Dolomitic Keuper members may rest uncomformably on the Lower Muschelkalk Member. In a belt inmediatly north of this fringe zone, these mebers may rest unconformably upon the lower Keuper members.
Distribution The formation is present in the Mesozoic basins and on the flanks of the platform areas. The most complete succession of the Keuper Formation is found in the Central North Sea Graben, Ems Low and Off Holland Low. In all other locations it is reduced in thickness, often greatly, by intra-Keuper erosion. Two distinct unconformaties occur within the Keuper succession (see also Wolburg (1969b) ), related to the Early Kimmerian tectonic movements. In the West Netherlands Basin the oldest unconformity results in the Red Keuper Claystone or the Dolomitic Keuper Member directly overlaying the Muschelkalk Formation. In the southern basin-fringe area the erosion related to this unconformity may cut into the Lower Muschelkalk Member. The effect of the youngest unconformity, which lays at the base of the Altena Group, appears to be restricted. On the paleo-highs in the central Netherlands the entire Keuper is absent below this uncoonformity, which renders it impossible to access the effect of each unconformity separately.
Age Late Ladinian-Norian
Depositional Setting The Keuper Formation comprises sediments laid down in a continental environment, displaying an alternation of fluvial, lacustrine and and evaporitic settings.
  The full Keuper succession consists of four claystone members alternating with three evaporitic intervals. This succession can be recognized clearly in the basinal areas( Central Graben, northern Off Holland Low, Ems Low). towards the southern basin fringe and on the Mid Netherlands Swell, the evaporitic members pinch out. The thick basinal halites grade into thin anhydrite or dolomite beds.
  For regional purposes, a simplified subdivision can be applied, in which the members above the Main Keuper Evaporite Member are lumped into one larger unit, informally called the Argillaceous Keuper member (RNKPC). e.g. in well L02-01:2808-3076 m and well Emmen-7: 1610-1641 m. NAM and RGD (1980)
  The subdivision of the complete developed Keuper Formation is:
  RN Upper Germanic Trias Group
  RNKP Keuper Formation
  RNKPU Upper Keuper Claystone Member
  RNKPD Dolomitic Keuper Member
  RNKPR Red Keuper Claystone Member
  RNKPE Red Keuper Evaporite Member
  RNKPM Middle Keuper Claystone Member
  RNKPS Main Keuper Evaporite Member
  RNKPL Lower Keuper Claysone Member
References See References Triassic

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