Texel Formation

CKTX

Formal (NAM & RGD 1980).

White to light-grey, locally pinkish limestones and marly chalks with some marly intercalations. In the south, glauconitic sands are present in the lowermost part of the formation. Along the southern North Sea basin margins (West Netherlands Basin, Maasbommel High) the formation starts with a basal transgress¡ve greensand. More distally, in the central West Netherlands Basin, the Broad Fourteens Basin and the Central Netherlands Basin this grades into increasingly marly deposits, which in turn change into pure limestones in the area north of these basins.

Transgressive marine environment in a relatively deep water.

The contact with the underlying Holland Formation is usually distinct; the marls and marly claystones of the Holland Formation exhibit a higher gamma ray response and lower acoustic velocity. In the West Netherlands Basin and the Broad Fourteens Basin the Holland Holland Formation is much thicker, and the transition is more gradual. In the vicinity of the Mid North Sea High - Elbow Spit High and above salt domes the unit locally rests unconformably upon deposits of the Zechstein Group, the Lower Germanic Trias Group or the Upper Germanic Trias Group.

The upper boundary with the overlying Ommelanden Formation normally coincides with the top of the Plenus Marl Member, which is expressed clearly on wire-line logs by a peak of high gamma-ray response and a low acoustic velocity.

Up to 870 m (Q01-26).

Widespread in the southern North Sea and the Netherlands onshore area, where its distribution roughly coincides with that of the Chalk Group. The formation's depositional realm did not include the northern flanks of the London-Brabant Massif and Rhenish Massif. The formation is also absent on the crest of the Mid-North Sea High Elbow Spit High, and in areas where the main inversion event occurred during the Santonian-Campanian (Subhercynian phase). The formation is exposed very locally in the Achterhoek, east of Winterswijk (Van Adrichem Boogaert 1975; Witte et al. 1992).

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

Cenomanian.

Named after the Dutch Wadden island of Texel.

None.

Mark Geluk, Geert-Jan Vis (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. 1975. Het Mesozoicum in Oost-Nederland. In: Zagwijn, W.H. and Van Staalduinen, C.J. (eds.): Toelichting bij geologische overzichtskaarten van Nederland, Rijks Geologische Dienst, Haarlem, 72-76.

Witte, L., Lissenberg, Th., Schuurman, H. 1992. Ostracods from the Albian/Cenomanian boundary in the Achterhoek area (eastern part of the Netherlands). Scripta Geologica 101, 33-84.