Deformation pattern of the Eastern Guadalquivir foreland basin (Southern Spain)

Reunión Ibérica sobre Fallas Activas y Paleosismología (3ª. 2018. Alicante)This contribution characterizes the deformation pattern of the eastern part of the Guadalquivir foreland basin and proposes the large-scale orogenic processes involved. The deformation pattern within the eastern Guadalquivir foreland basin has been characterized by combining seismic reflection profiles, boreholes and structural field data to output a 3D model. High-dipping NNE-SSW to NE-SW trending normal and reverse fault arrays deform the Variscan basement of the basin. These faults generally affect Tortonian sediments, which show syntectonic features sealed by the latest Miocene units. Curved and S-shaped fault-traces are abundant and caused by the linkage of nearby fault segments during lateral fault propagation. Preexisting faults were reactivated either as normal or reverse faults depending on their position within the foreland. At Tortonian time, reverse faults deformed the basin forebulge, while normal faults predominated within the backbulge. Along-strike variation of the Betic foreland basin geometry is supported by an increasing mechanical coupling of the two plates (Alborán Domain and Variscan basement) towards the eastern part of the cordillera. There, the initially subducted Iberian paleomargin was incorporated into the upper plate promoting the transmission of collision-related compressional stresses into the foreland since the middle Miocene. Nowadays, compression is still active and produces low-magnitude earthquakes likely linked to NNE-SSW to NE-SW pre-exiting faults reactivated with reverse oblique-slip kinematics. Seismicity is mostly concentrated around fault tips that are frequently curved in overstepping zones.Unidad de Granada, Instituto Geológico y Minero de España, EspañaUnidad de Sevilla, Instituto Geológico y Minero de España, EspañaUniversidad de Jaén, Españ