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 central Languedoc is based on both new paleontological and field data. Rodents from the newly discovered fossil mammal-bearing locality of Aigues-Vives and those recently extracted from the site of Servian give the chronological frame. The cartography of the sediments linked to the Messinian erosional phase, as well as those of the Pliocene sequence synthetized the field observations. A precise plotting is given both for the river system cut during the Messinian crisis (Orb, Herault, and some of their tributary streams) and for the Pliocene shoreline especially in the case of the rias formed at the time of the marine transgression. During the Messinian crisis, the bed of the Herault river was incised less than the other river beds because the limestones of the immediate upper part of the area allowed a deep burying of the water table. Central Languedoc illustrates a geodynamical evolution according to Clauzon's model of the Messinian endoreic eustatism for the Mediterranean. (C) Elsevier, Paris.