Eléments de réflexion sur la morphogenèse des plateaux de Vaucluse (France) : les apports du karst superficiel

Abstract

About the genesis of Vaucluse plateaux : the lessons from karstic landforms. The study of the principal forms of the surface karst gives a first diagram of evolution of the plates of Vaucluse. Paleo-surfaces now perched and/or deformed are witnesses old major phases of flattening, in regional matter, undoubtedly of ante-miocene age. The whole of intermediate surfaces (850 m) seems to cut the miocene deposits (Burdigalien ) of the ditch of AureUSault. It thus reveals a major phase of post-miocene flattening. These surfaces of karstic flattening were to be in relation to the vast poljes of the sectors of Saint-Christol and the ditch of Sault. Their genesis, dependent on dysfunctions of the etidokarstic drainage, could be related to the pliocene transgression. Canyon of Nesque, structuring elements major landscape, present, on both sides Rocher du Cire, two distinct parts, having own morphologies. The downstream part, wide open, would have grown hollow by headwater erosion from a karstic steephead perhaps since the end of Miocene. The narrow upstream part would have incised itself, after capture of the polje of Sault, undoubtedly at the time of the cold phases of the Quaternary one.