MESSINO-PLIOCENE GEODYNAMIC EVOLUTION IN THE LANGUEDOC CENTRAL - THE ORB AND HERAULT HYDROGRAPHIC PALEO-NETWORK (SOUTHERN FRANCE)

The proposed reinterpretation of the Upper Neogene geodynamics in cent ral Languedoc is based on both new paleontological and field data. Rod ents from the newly discovered fossil mammal-bearing locality of Aigue s-Vives and those recently extracted from the site of Servian give the chronological frame. The cartography of the sediments linked to the M essinian erosional phase, as well as those of the Pliocene sequence sy nthetized the field observations. A precise plotting is given both for the river system cut during the Messinian crisis (Orb, Herault, and s ome of their tributary streams) and for the Pliocene shoreline especia lly in the case of the rias formed at the time of the marine transgres sion. During the Messinian crisis, the bed of the Herault river was in cised less than the other river beds because the limestones of the imm ediate upper part of the area allowed a deep burying of the water tabl e. Central Languedoc illustrates a geodynamical evolution according to Clauzon's model of the Messinian endoreic eustatism for the Mediterra nean. (C) Elsevier, Paris.