Texel Marlstone Member

CKTXM

Formal (NAM & RGD 1980).

White to light-grey, locally pinkish, limestones and marly chalks. South of the Broad Fourteens Basin and in the western parts of the West Netherlands Basin, marls and marly chalks predominate, whereas further north these lithologies are restricted to the lower part of this member.

Relatively deep marine conditions, below wave base.

Generally placed at the base of a distinctly more calcareous interval overlying the Upper Holland Marl Member. In the basin-margin setting this boundary lies on top of the highest sandstones of the underlying Texel Greensand Member.

Placed at the base of the argillaceous Plenus Marl Member. Where this member is absent, the Texel Marlstone Member is overlain unconformably by the Ommelanden Formation. In this situation two limestone units are in direct contact, which complicates locating the boundary. It may be found by tracing the truncated beds in the Texel Marlstone Member, which usually has a somewhat more irregular wire-line log pattern than the overlying Ommelanden Formation.

Up to 250 m.

The member is widespread in the southern North Sea and the Netherlands onshore. It is absent in the southernmost part of the North Sea area and the southern Dutch onshore area, as well as in the centres of areas with Subhercynian and Laramide inversion.

UK: Hidra Formation; GER: Helgoland & Brochterbeck formations; BEL: Bernissart & Hainaut formations.

Cenomanian.

Named after the predominant lithology of the lower part of the member.

None.

Mark Geluk, Geert-Jan Vis (June 2017).

NAM & RGD 1980. Stratigraphic nomenclature of The Netherlands. Verhandelingen van het Koninklijk Nederlands Geologisch Mijnbouwkundig Genootschap 32, 77 p.