Gravity modelling of the litho-asthenosphere system in the Central Mediterranean

The results of the 2.5-D gravity modelling of the litho-asthenosphere system in the Central Mediterranean, along two regional geotransects, are presented and their possible implications for the geodynamical evolution of this area are discussed. Particularly, gravity data on the Tyrrhenian and Provencal-Balearic basins were interpreted introducing significant constraints by means of several main petro-physical parameters tied to the litho-asthenospheric evolution during the extensive tectonics. By this approach, based on the model of McKenzie and Bickle (in: J. Petrol., 29, pp. 625-679, 1988) and White and McKenzie (in: J. Geophys. Res., 94, B6, pp. 7685-7729, 1988), the estimation of the vertical density distribution in the lithosphere-asthenosphere system has been possible. Significant differences in the gravity anomaly field occur when different density models of asthenospheric upwelling are considered. This depends on factors like the thermal regime, the stretching of the lithosphere and its thickness before it. The obtained results contributed to the validation of models interpreting the origin of the Tyrrhenian and Ligurian-Provencal basins as related to a passive extensional process rather than to the presence of an active upwelling asthenosphere beneath the Central Mediterranean basins. (C) 1998 Elsevier Science B.V. All rights reserved.