Bollen Claystone Formation OBGC


Premise Informal unit, defined by Van Adrichem Boogaert and Kouwe (1994).
Derivatio nominis Named after the Bollen van Goeree, a shoal in the southern North Sea off the island of Goeree-Overflakkee.
Type section Location map See figure (pdf)
  Well S05-01 (pdf)
  Location N 51°47’33.2
E 03°33’47.8
  Depth 2005 to 2230 m
  Length 225 m along hole
Additional section Location map See figure (pdf)
  Well S02-02 (pdf)
  Location N 51°51’21.7
E 03°36’32.3
  Depth 2836 to 2878 m
  Length 42 m along hole
Definition Formation consisting of dark shaly mudstones and some intercalated, thin, white to greenish-grey, fine-grained sandstones. The unit is in places slightly calcareous or dolomitic.
Upper Boundary Where the succession is complete, the Bollen claystone is overlain by the heterolithic Bosscheveld deposits. The upper boundary has been placed at the base of the first distinctive sandstone/limestone beds. In absence of the Bosscheveld formation, the Bollen claystone is directly overlain by the massive carbonates of the Zeeland Formation.
Lower Boundary Data on the lower boundary are not available.
Correlation The lateral equivalent of the Bollen claystone in the Belgian Doornik Basin is the Bovesse Formation (pers. comm. Mr. M. Dusar; Coen_Aubert (1980) . This predominantly argillaceous unit contains a number of prominent limestone intercalations and is underlain by the sandy and calcareous Mazy Formation (Givetian).
Distribution In the Dutch sector of the North Sea, continental Devonian deposits have been encountered in a small number of wells only on and around the Mid North Sea High and the Elbow Spit High. In combination with information from wells drilled in the UK sector, a better understanding of the stratigraphy could be achieved. In part, the British stratigraphic nomenclature Cameron (1993a) Cameron (1993b) has been adopted for the Netherlands.
Age No firm age determination is available for the Bollen claystone. However, similarities with the Bovesse Formation suggest a Frasnian age.
Depositional Setting The unit was deposited in a low-energy shelf, shoreface to transitional-marine setting.
References See References Devonian and Lower Carboniferous

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