EARLY VARISCAN, SOFT-SEDIMENT DEFORMATION FEATURES IN THE CHEMIN DE RONDE SECTION AT THE NAMUR CITADEL(BELGIUM)
Structurele Geologie en Tektoniek, K.U. Leuven , Redingenstraat 16, B-3000 Leuven
Stratigrafie, K.U. Leuven , Redingenstraat 16, B-3000 Leuven
Structurele Geologie en Tektoniek, K.U. Leuven , Redingenstraat 16, B-3000 Leuven
Abstract
ABSTRACT. A detailed geometrical study of the Chemin de Ronde section at the Namur Citadel (Meuse River side) and an attempt to reconstruct its original sedimentary configuration, demonstrates that these Namurian sediments were affected by (at least) three types of deformation from their deposition onwards until their final incorporation in the Variscan foreland fold-and-thrust belt. Regularly occurring palaeoseismites reflect the onset of the Variscan deformation in the basin at the time of deposition. A major penecontemporaneous, soft-sediment deformation event occurred when the sediments were affected by the early stages of the Variscan orogeny at the tip of the accretionary complex in front of the prograding orogen. Finally, these Namurian rocks underwent a hard-rock deformation at the time these rocks were incorporated in the Variscan foreland fond-and-thrust belt.
The presence of these three types of deformation features in one single outcrop reflects a prograde deformation history over a period of ~30Ma, from penecontemporaneous soft-sediment deformation during and shortly after deposition to hard-rock deformation during the peak stages of orogeny.