Main Claystone Formation

Formal (NAM & RGD 1980). Amended (Van Adrichem Boogaert & Kouwe 1994).
Lithological description

Rred-brown to green, silty, sometimes anhydritic claystone. Some thin sandstone beds and oolitic beds also occur.

Depositional setting

Presumably a near-shore, shallow water depositional setting.

Definition of lower boundary

Characterized by a, generally thin, sandstone bed which overlies the Zechstein fines.

Definition of upper boundary

Placed at the base of the first prominent oolite bed.

Thickness indication
Up to 375 m.
Geographical distribution
Regional correlation
UK: Bacton Group; GER: Calvörde Formation; BEL: Main Claystone Member.
late Changhsingian - Induan.
Depth (thickness) AH:
3066 - 3255 m (189 m)
Depth (thickness) AH:
1732 - 1973 m (241 m)
Origin of name
Previous name(s)
Main Claystone Member.
Reviewed by (date)
Johan ten Veen (2017).
NAM & RGD 1980. Stratigraphic nomenclature of The Netherlands. Verhandelingen van het Koninklijk Nederlands Geologisch Mijnbouwkundig Genootschap 32, 77 p.
Van Adrichem Boogaert, H.A. & Kouwe, W.F.P. 1994. Stratigraphic nomenclature of The Netherlands; revision and update by RGD and NOGEPA, Section E, Triassic. Mededelingen Rijks Geologische Dienst, 50, 1-28.
Cite as
TNO-GDN ([YEAR]). Main Claystone Formation. In: Stratigraphic Nomenclature of the Netherlands, TNO – Geological Survey of the Netherlands. Accessed on [DATE] from