THE LATE OLIGOCENE-MIOCENE OPENING OF THE NORTH BALEARIC SEA (VALENCIA BASIN, WESTERN MEDITERRANEAN) - A WORKING HYPOTHESIS INVOLVING MANTLE UPWELLING AND EXTENSIONAL DETACHMENT TECTONICS

The North Balearic Sea (Valencia basin) is one of the western Mediterranean basins that opened during the late Oligocene-Miocene. However, in contrast with neighbouring basins, the Valencia basin is floored by highly attenuated continental crust. The geological and geophysical characteristics of this realm indicate that extensional tectonics and mantle instability played a major role in the opening of the basin and consequent SE-directed drifting of its eastern flank (Balearic Rise). A model for the generation of this basin is proposed, involving the intrusion of asthenospheric mantle and subsequent extensional detachment tectonics during late Oligocene-Miocene times. This model accounts for the asymmetrical rifting of the North Balearic Sea, and the clockwise drifting/rotation of the Balearic Rise. © 1990.