Age of extensional detachments in the northwestern Gibraltar Arc system through onshore-offshore correlations

Resum

The Miocene tectonic evolution of the Gibraltar Arc system is characterized by the simultaneous formation of a fold-and-thrust belt in the external zones while a back-arc basin was formed in its hinterland.At the northwestern part of the internal zones of the arc, the lack of syn-tectonic Miocene deposits onshore prevents to constraint the age of the extensional systems involved in the rifting. In order to better constraint the age of these structures we focus on the analysis of the sedimentary cover offshore and correlate them with the extensional structures through onshore-offshore cross-sections. This has allowed to differentiate two main episodes within the Miocene rifting. The Aquitanian-Burdigalian episode is related with the major thinning and exhumation of the Alboran Domain with two mayor transport directions of the hanging wall block towards the SW and SSE, respectively. The Langhian-early Tortonian episode corresponds with the opening of the Malaga Basin and was characterized by transport towards the NW.