Late Tertiary fault activity in the Southwestern boundary fault system of the Roer Valley Graben: Evidences from the Bree area (NE Belgium)

Abstract

The Bree Uplift is a particular structure in the direct footwall of the southwestern graben boundary fault system of the Roer Valley Graben, which has been firstly recognized at the base of the Cretaceous. To date fault activity around the Bree Uplift has been confined to the Subhercynian (late Cretaceous) inversion event or considered fading out during Tertiary times. The revision of the existing geological data reveals that the Bree Uplift can still be recognized on the top-Tertiary map. This infers at least a late Tertiary activity, suggesting continuous fault activity in the graben boundary fault system not only on the major boundary faults but also on different splay faults, bounding individual fault blocks.