Gravimetric survey and modelling of a tectonic indenter boundary: The Palomares Fault Zone (Betic Cordillera, Iberia)

Abstract

New gravimetric data are improving our understanding of the Palomares Fault Zone (PFZ) that accommodates the Águilas Arc tectonic indentation (eastern Betic Cordillera, SE Iberia) in the context of the Eurasia-Africa convergence. The PFZ limits the sedimentary infill geometry of the Vera and Pulpí Basins, and the western Guadalentín Corridor, which are located along the western boundary of the arc. Gravity anomaly models are in agreement with previous tectonic interpretations that suggest that the PFZ fragments and bends the depocenters of those basins, as it has been proposed for the antiforms (ranges) that are located eastwards. Furthermore, the gravity anomaly models show that the PFZ extends from the Cabrera Range to the Almagrera Range and ends in the north at the Pulpí Basin, where the basin infill is only deformed by a gentle symmetrical synform. As a consequence, the PFZ is (i) confined to the southern zone, where the deformation is most intense due to the displacement of the tectonic indenter, and (ii) disconnected from the front of the Águilas Arc and the Alhama de Murcia Fault (part of the Eastern Betic Shear Zone, EBSZ). The new extend of the PFZ we have documented supposes the structural segmentation of the EBSZ and reduces both seismotectonic and structural significances of the PFZ. The study of the PFZ shows that the boundaries of the indenter are the locus for diffused deformation accommodated by local-scale faulting along with structural rotations and deflections, rather than localized strike-slip faulting along the whole indenter margin.