2.1.3. Pommeroeul Greensand Formation - POM

Authors: Marlière (1936b); Robaszynski (1975).

Description: Conglomerates of Palaeozoicrocks, coarse sands, fine sands and sandstonescolouredby grass green ferruginous clays (a very characteristic shade of green). A few levels contain lignites, which are probably reworked from continental deposits (Wealden facies). The marine fauna is very poor.

Stratotype: Disused pits at Harchies (Marlière, 1939).

Area: This formation is found only in the deepest parts of the Mons Basin, in the subsiding zones of Harchies and Pommeroeul. It represents the oldest portion part of the Cretaceous transgression in the Basin.

Thickness: 23 m in the Harchies pit.

Age: Middle Albian on the basis of Actinoceramus concentricus, Hoplites sp. near the top of the formation.

Remarks:This is the equivalent of the "Assise de Pommeroeul" of Marlière (1936a, b, 1939, 1957), raised to the rank of a Formation by Robaszynski (1975).