ABSTRACT
At the end of the Miocene, the Rhone River valley was subjected to an exceptional event, the “Messinian Salinity Crisis”. The oscillation of the Mediterranean Sea base level created deep canyons which were filled during the Pliocene. The most spectacular hydrogeological consequences of this was the extensive karstification of the Cretaceous limestone in the Rhone River valley. These affected all the aquifers which are in contact with Messinian karst or the Pliocene fill material in the Rhone River canyons. This paper gives three examples from the foreland basins along the Rhone River valley (the basins of Valence, Valréas and Carpentras). It shows that deep groundwater resources exist at the base of the Pliocene filling and emphasizes the hydraulic connections between karstic, basinal and Pliocene aquifers. These results are characteristic of all peri-Mediterranean river basins.
