Formal (Van Adrichem Boogaert & Kouwe 1994).
Red-brown to grey dolomitic claystone, interbedded with thin anhydrite layers. A distinct anhydrite layer in the basal part can be distinguished separately as the Z2 Fringe Anhydrite Member. In the western offshore sandstone beds may be intercalated. Towards the fringe the amount of sandstone increases.
Definition of lower boundary
Along the basin fringe, in places with a prevailing argillaceous development, it may be impossible to discern the boundary with the underlying Red-Brown Salt Clay Member with certainty.
Definition of upper boundary
UK: ?; GER: ?; BEL: Z2 Middle Claystone Member.
Van Adrichem Boogaert, H.A. & Kouwe, W.F.P. 1994. Stratigraphic nomenclature of The Netherlands; revision and update by RGD and NOGEPA, Section D, Permian. Mededelingen Rijks Geologische Dienst, 50, 1-42.
TNO-GDN ([YEAR]). Z2 Middle Claystone Member. In: Stratigraphic Nomenclature of the Netherlands, TNO – Geological Survey of the Netherlands. Accessed on [DATE] from http://www.dinoloket.nl/en/stratigraphic-nomenclature/z2-middle-claystone-member.