2.10.1. Zelzate Formatie - Zz

Authors: Jacobs (1975, 1978), Jacobs & Vandenberghe (1988).

Description: This marine unit starts with a dark grey, moderately fine, silty sand, glauconiferous and micaceous, with intercalations of thick lenses of grey clay; it is covered by dark green, sandy clay. The top is formed by green grey sands, rich in fos-sils, with large sandstone concretions.

Stratotype: stratotypes have only been designated for the members.

Area: northern part of East-Flanders and the Antwerpen Province till the area between the Nete and the Demer rivers.

Members: the formation is subdivided into the Bassevelde Mbr, Watervliet Mbr and the Ruisbroek Mbr.

Thickness: probably 25 to 30 m, decreasing to the east.

Age: Early Priabonian to Early Oligocene.

Remarks: the formation is also discussed by Dumont (1839), Gulinck (1965b, 1969), Halet (1905, 1937), Jacobs & De Coninck (1977), Janssen (1981), Matheussens (1971), Mourlon (1894-1895), Steurbaut (1986, 1992), Vandenberghe (1974) and Van Den Bosch et al. (1975).