Voort Member

Best described as a stacking of coarsening-upwards sequences at the scale of tens of metres. The proportion of clays is highest in the lower upper part of the member. The uppermost part stands out on logs as a relatively homogeneous and clean sand. The member is well-developed in the Roer Valley Graben. On the Peel and Venlo blocks the proportion of argillaceous sediments is very low. The sands are fine-grained, grey-green and glauconitic. Locally the sands may have a dark grey-green to black colour and comprise glauconites, marine molluscs and otoliths.

Middle neritic to littoral marine environment. The topmost sands seem intensively reworked.

Conformably or mildly unconformably overlies the Steensel Member or the Boom Member of the Rupel Formation. In the southern distribution area of this member, the boundary is placed at the base of a distinct clay layer.

Overlain by the clays that constitute the middle part of the Veldhoven Formation. In the axial zone of the Roer Valley Graben the boundaries are conformable.