CONTRIBUTION TO THE STRUCTURAL AND SEDIMENTARY HISTORY OF THE GULF OFLIONS (WESTERN MEDITERRANEAN), FROM THE ECORS PROFILES, INDUSTRIAL SEISMIC PROFILES AND WELL DATA

Data from 11 wells, a dense seismic grid, and the ECORS deep seismic p rofiles provide a precise picture of the geological history of the Gul f of Lions. 4 sequences are identified from the late Oligocene-early M iocene synrift to the Pliocene-Quaternary progradational shelf. The mi ddle Miocene is characterized by a highstand system tract established on a palcoshelf. These seismic-stratigraphical observations can be pla ced into their tectonic framework. The Gulf of Lions area first underw ent a compressional phase related to the Pyrenean orogeny, then a late r extensional phase caused by the opening of the Provencal basin. When suitably oriented, the former thrusts are reactivated as detachment d ue to subsequent extension.