Superposition of tectonic structures leading elongated intramontane basin: the Alhabia basin (Internal Zones, Betic Cordillera)

Abstract

The relief of the Betic Cordillera was formed since the late Serravallian inducing the development of intramontane basins. The Alhabia basin, situated in the central part of the Internal Zones, is located at the intersection of the Alpujarran Corridor, the Tabernas basin, both trending E–W, and the NW–SE oriented Gador–Almeria basin. The geometry of the basin has been constrained by new gravity data. The basin is limited to the North by the Sierra de Filabres and Sierra Nevada antiforms that started to develop in Serravallian times under N–S shortening and to the south by Sierra Alhamilla and Sierra de Gador antiforms. Plate convergence in the region rotated counter-clockwise in Tortonian times favouring the formation of E–W dextral faults. In this setting, NE–SW extension, orthogonal to the shortening direction, was accommodated by normal faults on the SW edge of Sierra Alhamilla. The Alhabia basin shows a cross-shaped depocentre in the zone of synform and fault intersection. This field example serves to constrain recent counter-clockwise stress rotation during the latest stages of Neogene–Quaternary basin evolution in the Betic Cordillera Internal Zones and underlines the importance of studying the basins’ deep structure and its relation with the tectonic structures interactions.