Reddish and dark-coloured claystones, alternating with thin layers of dolomite and fine-grained sandstone. Some coaly material occurs in the lower part of this member (Geluk, 2005); this is probably carbonized plant matter. The lower part is characterised by greyish colours, in the upper part red or red-brown colours predominate. The anhydrite content gradually increases towards the top.
Definition of lower boundary
Definition of upper boundary
The greatest thickness, up to 200 m, occurs in the southern part of the Dutch Central Graben. In other areas, the thickness of the member is typically between 40 and 80 m.
UK: Dudgeon Formation; GER: Erfurt Formation (Lettenkeuper); BEL: Lower Keuper Claystone Member.
Geluk, M.C. 2005. Stratigraphy and tectonics of Permo-Triassic basins in the Netherlands and surrounding areas. PhD Thesis, Utrecht University, 171 p.
NAM & RGD 1980. Stratigraphic nomenclature of The Netherlands. Verhandelingen van het Koninklijk Nederlands Geologisch Mijnbouwkundig Genootschap 32, 77 p.
TNO-GDN ([YEAR]). Lower Keuper Claystone Member. In: Stratigraphic Nomenclature of the Netherlands, TNO – Geological Survey of the Netherlands. Accessed on [DATE] from https://www.dinoloket.nl/en/stratigraphic-nomenclature/lower-keuper-claystone-member.