Dongen Formation NLFF


Premise Originally defined by NAM and RGD (1980)
Derivatio nominis Named after the Dutch municipality of Dongen in the province of Noord-Brabant.
Type section Location map See figure (pdf)
  Well Dongen-1 (pdf)
  Location N 51°37'37.0
E 04°54'48.2
  Depth 691 to 993 m
  Length 302 m along hole
  Reference NAM and RGD (1980)
Additional section Location map See figure (pdf)
  Well L02-04 (pdf)
  Location N 53°51'22.2
E 04°38'59.2
  Depth 1007 to 1532 m
  Length 525 m along hole
  Reference NAM and RGD (1980)
Definition Formation of dark-grey, green and brown, slightly calcareous clays, with an intercalated, glauconitic sand to sandstone body, which grades distally into a marly unit. The lowermost part of the formation is characterised by tuffaceous clays and is sandy in a proximal position. In the southwesternmost part of the country, the formation probably comprises continentally influenced deposits at its base.
Upper Boundary In areas where the succession is virtually complete, the upper boundary of the formation is marked by the usually clear transition from its upper argillaceous part to the unconformably overlying sands of the Vessem Member of the Rupel Formation. Around the eroded ‘Southern Early Tertiary High’ and its northwestern extension into the North Sea, an unconformable contact with various Dongen Formation members with the overlying formations exists. In those areas where the Vessem Member is absent, the Rupel Clay Member rests directly on the clays of the Dongen Formation. In that case, determination of the boundary on lithological grounds may be difficult. However, on wire-line logs the Rupel Clay Member shows a somewhat higher gamma-ray response compared to the clays of the Lower North Sea group. Micropalaeontological criteria are commonly applied to assist in defining this boundary.
Lower Boundary Generally, the lowermost boundary is characterised by a sharp transition from the Landen Clay member to the sandy or tuffaceous base of the Dongen Formation. The contact is conformable to mildly unconformable. In the southern Netherlands, where the underlying Landen Formation has a regressive sandy top, the boundary is less clear (see paragraph 2.2.1 under Boundaries). In the easternmost parts of the provinces of Gelderland and Overijssel, the formation unconformably overlies Mesozoic deposits.
Distribution The formation is present in most of the Netherlands on- and offshore area, with the exception of the southeastern and easternmost parts of the country, and a zone of erosion on the ‘Southern Early Tertiary High’.
Age Early and Middle Eocene (Ypresian to Bartonian). The formation is thought to cover the time interval characterised by the NP 11 to NP 17 nannoplankton zones. The foraminiferal assemblages are characteristic of the FI and FH zones.
Depositional Setting Marine deposit, with a transgressive basal part. Mainly inner to outer neritic.
Sequence Stratigraphy The Dongen Formation as a whole spans the Ypresian to the Bartonian and represents sequences TA 2.4 to TA 3.6. The sequence stratigraphic interpretation, as presented in Figure I.5 is rather speculative.
  The Dongen Formation has been subdivided into seven members as follows:
  NLFF Dongen Formation
  NLFFB Asse Member
  NLFFM Brussels Marl Member
  NLFFS Brussels Sandstone Member
  NLFFY Ieper Member
  NLFFT Basal Dongen Tuffite Member
  NLFFD Basal Dongen Sand Member
  In the northern offshore area, the Brussels Marl Member becomes gradually less calcareous and tends to lose its identity. There, the argillaceous sediments equivalent to the Ieper, Brussels Marl and Asse Members can be combined into the informal
  NLFFC Dongen Clay Member
  It consists of dark-grey to greenish grey, usually slightly calcareous clays.
References See References Tertiary

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