Multi-scale Seismic Imaging of the Strike-slip Yussuf Fault System (Alboran Sea)

Hector Perea Manera, Eulàlia Gràcia, Rafael Bartolome, César R. Ranero, Claudio Lo Iacono, Sara Martínez-Loriente, and Ximena Moreno

The NW-SE convergence (4-5 mm/yr) between the African and Eurasian plates controls the presentday crustal deformation along the southern Iberian and northern African margins. The strain due to this convergence is partially accommodated over the Alboran Sea. During the EVENT-DEEP and TOPOMED cruises bathymetric data and multichannel seismic (MCS) profiles were acquired to investigate the fault systems located in the Alboran basin, among them the Yussuf fault system. This is a right-lateral strike-slip fault system with WNW-ESE trend that has produced the formation of the Yusuf pull-apart basin. The preliminary analysis of the acquired MCS profiles shows that: a) the fault system is a composed by several strike-slip faults fairly vertical; b) these faults join in a common fault plane at depth; and c) some of the faults reach the sea-floor surface and in some places offset it, implying the Quaternary activity along the fault system. Moreover, three zones have been distinguished along the fault system. The Yusuf lineament is the westernmost zone and is characterized by a vertical fault zone that put in contact a thinned continental crust, on the upthrown block, with a magmatic arc crust, on the downthrown block. To the east, there is the Yusuf basin that deepens eastwards. Different faults structure the zone and produce the uplift of the Yusuf Ridge. As in the previous zone, the presence of the fault system separates a thinned continental crust from a magmatic arc crust. Finally, the Habibas escarpment is the easternmost zone, where the fault system becomes narrower and seems to be the limit between a thinned continental crust and a possible oceanic crust. Much analysis is needed in order to accurately characterize the Yusuf fault system.

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