The tectono-metamorphic evolution of the Veleta Complex and the development of the contact with the Mulhacen Complex (Betic Zone, SE Spain)

Abstract

Four phases of penetrative deformation (D1vel to D4vel) have been distinguished in the uppermost 0.5 km of the Veleta Complex, the lowest in the stack of four nappe complexes of the Betic Zone.-Ihe contact of the Veleta Complex with the overlying Mulhacen Complex is parallel to S2, which is the main tectonic foliation in both complexes. The rotation sense of synkinematically grown D2vel garnets and the asymmetry of preferred orientations of quartz c-axes in mylonites in the highest part of the Veleta Complex demonstrate top-to-the-west shear, pointing to a westward movement of the Mulhacen Complex. The nappe contact was folded and locally overturned during D3vel, demonstrating that the tectonic contact was formed during D2vel. During D4vel the nappe contact was reactivated as shown by concentration of extensional structures in the uppermost 20m of the Veleta Complex. It is argued that reactivation occurred during overthrusting of the Alpujarride Complex at higher structural level. Although metamorphism of the graphite-rich pelites has not resulted in characteristic mineral assemblages, the relationship between mineral growth and deformation shows that, during the early tectonic evolution, both pressure and temperature in the Veleta Complex were lower than in the overlying Mulhacen Complex.