Basal Dongen Sand Member NLFFD

 

Premise Originally defined by NAM and RGD (1980) .
Derivatio nominis Named after the municipality of Dongen in the province of Noord-Brabant. Basal refers to the basal position within the formation.
Type section Location map See figure (pdf)
  Well Dongen-1 (pdf)
  Location N 51°37'37.0
E 04°4'48.2
  Depth 985 to 993 m
  Length 8 m along hole
  Reference NAM and RGD (1980)
Additional section Location map See figure (pdf)
  Well Veldhoven-1 (pdf)
  Location N 51°26'20.8
E 05°21'37.2
  Depth 1259 to 1279 m
  Length 20 m along hole
Definition Light green-grey, locally glauconitic, usually thin sand with a fining-upward character. It can be very argillaceous, and may locally contain some well-cemented layers. In the southeastern part of the province of Noord-Brabant, the Basal Dongen Sand Member comprises several sand bodies separated by clay beds, the sand bodies can be up to 20 m thick. Blue-violet to grey tuffaceous intercalations occur at the northern extent of this unit's distribution, mainly in its middle or upper part. Continentally influenced deposits (with sand and humic clay with wood fragments in well Woensdrecht, R.O.D.-17, interval 600-612 m: Jaarverslag R.O.D., 1912), which occur in the southwesternmost part of the country apparently at this stratigraphic level, have provisionally been attributed to the Basal Dongen Sand Member. These deposits may be partly equivalent with the Knokke Member of the Tienen Formation of the Belgian lithostratigraphy Marechal and Laga (1988) .
Upper Boundary The upper boundary is formed by a rather sharp transition to the Ieper Clay Member.
Lower Boundary Generally, the lower boundary is formed by a sharp transition to the argillaceous Landen Member. Only in the southeastern Netherlands, where this unit is overlain by the Reusel Member, can the boundary be less obvious. However, the latter is a coarsening-upward, more argillaceous, small-scale alternation of sand and clay layers with higher gamma-ray readings whereas the Basal Dongen Sand is fining upward, clean, reworked and yields low gamma-ray readings.
Distribution The member is present in the southern and central part of the Netherlands and the adjacent offshore area. It is absent in southern Limburg and the easternmost parts of the country, and a zone of erosion on the ‘Southern Early Tertiary High’.
Age Early Eocene (Ypresian). The unit does not contain calcareous microfossils.
Depositional Setting Shallow-marine, transgressive basal sand.
Sequence Stratigraphy The unit represents the Transgressive systems tract of cycle TA 2.4.
References See References Tertiary

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