Informal (Van Adrichem Boogaert & Kouwe 1994).
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.
Low-energy shelf, shoreface to transitional-marine setting.
Definition of lower boundary
Definition of upper boundary
Placed at the base of the first distinctive sandstone/limestone beds. In absence of the Bosscheveld formation, the Bollen claystone formation is directly overlain by the massive carbonates of the Zeeland Formation. Where the succession is complete, the Bollen claystone formation is overlain by the heterolithic deposits of the Bosscheveld formation.
Origin of name
Named after the Bollen van Goeree, a shoal in the southern North Sea off the island of Goeree-Overflakkee.
Van Adrichem Boogaert, H.A. & Kouwe, W.F.P. 1994. Stratigraphic nomenclature of The Netherlands; revision and update by RGD and NOGEPA, Section B, Devonian and Dinantian. Mededelingen Rijks Geologische Dienst, 50, 1-20.
TNO-GDN ([YEAR]). Bollen Claystone formation. In: Stratigraphic Nomenclature of the Netherlands, TNO – Geological Survey of the Netherlands. Accessed on [DATE] from https://www.dinoloket.nl/en/stratigraphic-nomenclature/bollen-claystone-formation.