2.8.3. Lede Formation - Ld

Authors: Mourlon (1873), Fobe (1988).

Description: this marine unit consists of calcareous and glauconiferous, fine sand. Some layers of sandy limestone or calcareous sandstone occur (normally three). The base is formed by a pebble layer with reworked elements (fossil fragments and rock fragments) from older deposits. The stone layers are frequently associated with coarse sediment layers (with the coarse base too). Nummulites variolarius is abundantly present.

Stratotype: Oosterzele - Balegem Quarry. Sheet 22/5-6, (Gavere - Oosterzele). Co-ordinates: x = 110.8, y 179.10, z = +66 m.

Area: the formation occurs in the north of East-Flanders Flanders and Brabant and in a large part of the Antwerp Province. It continually outcrops in the Dender-Zenne region and forms the subsoil of the Flemish Valley in a narrow zone between Zomergem and Dendermonde. It occurs in outliers, as the southern hills of West- and East-Flanders and adjacent areas of Hainaut and Brabant.

Members: the formation is not subdivided into members.

Thickness: 10 to 15 m.

Age: Middle Lutetian.

Remarks: the Lede and Brussels formations are also discussed by Dumont (1839, 1851), Fobe (1986, 1988), Fobe & Spiers (1992), Gulinck & Hacquaert (1954), Houthuys & Gullentops (1985, 1988), Kaasschieter (1961), Leriche (1912), Mignion (1969), Mourlon (1873, 1880, 1887), Rijksgeologische Dienst & Nederlandse Aardoliemaatschappij (1980), Rutot & Vincent (1879), Subgroup Lithostratigraphy and Maps (1980) and Vincent (1887),Houthuys, R., (2011), A sedimentary model of the Brussels Sands, Eocene, Belgium. Geologica Belgica, 14: 55-74.