The Crustal Domains of the Alboran Basin (Western Mediterranean)

Abstract

Abstract The Alboran Basin in the westernmost Mediterranean hosts the orogenic boundary between the Iberian and African plates. Although numerous geophysical studies of crustal structure onshore Iberia have been carried out during the last decade, the crustal structure of the Alboran Basin has comparatively been poorly studied. We analyze crustal‐scale images of a grid of new and reprocessed multichannel seismic profiles showing the tectonic structure and variations in the reflective character of the crust of the basin. The nature of the distinct domains has been ground‐truthed using available basement samples from drilling and dredging. Our results reveal four different crustal types—domains—of the Alboran Basin: (a) a thin continental crust underneath the West Alboran and Malaga basins, which transitions to (b) a magmatic arc crust in the central part of the Alboran Sea and the East Alboran Basin; (c) the North African continental crust containing the Pytheas and Habibas subbasins; and (d) the oceanic crust in the transition toward the Algero‐Balearic Basin. The Alboran Basin crust is configured in a fore‐arc basin (West Alboran and Malaga basins), a magmatic arc (central and East Alboran), and a back‐arc system in the easternmost part of the East Alboran Basin and mainly Algero‐Balearic Basin. The North African continental crust is influenced by arc‐related magmatism along its edge and was probably affected by strike‐slip tectonics during westward migration of the Miocene subduction system. The distribution of active tectonic structures in the current compressional setting generally corresponds to boundaries between domains, possibly representing inherited lithospheric‐scale weak structures.