Crustal Structure and Deformation of the Balearic Promontory: Insights from a Seismic and Gravimetric Study

Olivier Driussi, Agnès Maillard, and Anne Briais

The Balearic Promontory is a NE-SW continental high located in the Western Mediterranean basins forming the northeastern extremity of the Betics. The promontory is surrounded by two extensional basins opened during Oligo-Miocene times: the Valencia Trough to the north which is an aborted rift and the Algerian basin to the south, an oceanic crust basin which separates the southern margin of the promontory from the Algerian inverted margin. These basins are interpreted to have formed by a rapid rollback of the tethysian slab subducting under the Eurasian plate.

The history of the western basins is still fragmentary. The northern margin of the Balearic Promontory underwent the opening of the Valencia rift and the thrusting in the Betics, both events known to be synchronous during Miocene time. The southern margin of the Promontory, mostly characterized by the narrow and abrupt escarpments of Emile Baudot and Mazaron, is linked to the kinematics of the South Balearic-Algerian basin which is currently unknown. On the one hand, the actual morphology of the scarps is interpreted to reflect E-W transpressive faults. On the other hand, several models suggest that the opening of the South Balearic-Algerian basin has been in a N-S direction.

We use seismic lines, recent gravimetric grids and field studies to characterize the structure of the area and propose a timing of the deformation. The seismic lines show extensional and compressionnal deformation from the Neogene to Present. Deformation of the Messinian Salinity Crisis markers, ubiquitous on the Promontory and its surroundings, suggests inversion of the area. The gravimetric sections are used to constrain the crustal structure of the Promontory and the oceanic-continental transition with the aim to propose a new geodynamic model of the region.

AAPG Search and Discovery Article #90161©2013 AAPG European Regional Conference, Barcelona, Spain, 8-10 April 2013