Tectonic evolution of the Alpujárride Complex (Betic Cordillera, southern Spain)

Abstract

The Alpujárride Complex, belonging to the Internal Zones of the Betic Cordillera, is an E-W elongated domain of metamorphic nappes, which extends over more than 400 km in southern Spain. The Alpujárride Complex suffered two shearing episodes defined by different kinematic and physical conditions. The first one involved ductile thrusting from the south-west towards the north-east, related to the regional metamorphism of the Alpujárride nappes. This process led to crustal thickening, related to which the hot thrusting of the Ronda peridotites occurred. The second shearing episode, directed northwards, occurred after the metamorphism. It corresponds to a deformation in the brittle-ductile transition that led to the thinning of the crust thickened in the previous episode. Previous tectonic models of the Betic Cordillera have only considered the northwards shearing, which reflect the N-S convergence of Europe and Africa from the Oligocene onwards. The present work clearly points to the existence of previous episodes of ductile thrusting towards the north-east that reflect an earlier process of continental collision and that in future should be considered in tectonic models of the Betic orogen.