2.1.2.2.Vosselaar Member - BrV

Authors:Frieda Bogemans

Description:

This unit consists of several small fining up cycles predominantly composed of grey bad sorted very fine to medium fine sand containing up to 20% particles smaller than 63µm. Glauconite is common but in low concentration. The topfacies per cycle varies in grain size from fine sand to clay and may contain vegetation remains or be peaty.  The topfacies is composed of both simple and composite bedsets.  The maximal thickness of the observed topfacies is 20cm, 10 cm is more common.   

Stratigraphic position: The Vosselaar Member lays on top of the Brasschaat Member, but has a much more restricted distribution.

Stratotype: Drilling 17W181 (DOV kb8d17w-B36, coordinates: x = 184.821, y = 223.389).

Area:In restricted zones in the southern part of the northern Campine area.

Thickness: May reach a maximum thickness 9m.

Age: Lower-Pleistocene

Remarks:

-          Concerning the archives of the Geological Survey of Belgium: in the areas where both the Merksplas Formation and the Malle Formation are present, the Vosselaar Member (or the complete Malle Formation) is not defined, it is incorporated in the Merksplas Formation.

-          When the thickness of the topfacies is very small and/or the composition of the topfacies is rather similar to the rest of the deposits, in disturbed drillings one cannot differentiate the Vosselaar Member from the Brasschaat Member.