The role of the Ronda basin on the accommodation of different transport directions along the western Gibraltar Arc (last 10 my)

Zusammenfassung

Structures that give rise intermontane basins within fold-and-thrust belts may act as transference zones. In this work, we study the S Ronda basin boundary, apex part of the Gibraltar arc, to discuss its role as a transfer zone in the fold- and-thrust belt evolution during the last 10 My. This S boundary is characterized by the continuation of the Upper Mioce- ne-Recent normal fault zone of the NE boundary (BNFZ). This array of fault together with those of the SW boundary do not penetrate farther S, locating the S tip of the Ronda basin at its S boundary. The presence of this tip would imply counter clockwise vertical axis rotations of the W margin respect to the E margin. These rotations are congruent with variations of slip directions in normal faults and the radial tectonic transport of upper Miocene-Recent shortening structures within this fold-and-thrust belt segment located at the apex of the Gibraltar arc. This strain partitioning mode and basin inception are similar to those expected by analogue models of progressive arcs.