Petrofábrica del cuarzo en tectónicas del Corredor Blastomilonítico de Badajoz -Córdoba (SW del Macizo Ibérico). Aplicación a la cinemática de desplazamientos

Abstract

A study dealing with quartz microstructures and -C- axis fabrics within mylonite-series rocks from the Badajoz-Córdoba Ductile Shear Belt (SW Iberian Massif) is presented. Deformation regimes, geometries, temperatures, and kinematics are determined, as well as deformation histories responsible for the development of crystallographic preferred orientations (pan-african and variscan orogenic episodes). The geometry of variscan deformation (alternating areas with upright and horizontal mylonitic foliations containing ultramylonitic corridors) and mechanisms (complex deformation regimes characterized by the presence of neighbouring rock volumes affected by heterogeneous simple shear, flattening, heterogeneous simple shear plus flattening, buckling followed by flattening, etc.) are discussed from the perspective of deformation dynamics within ductile shear zones. Variscan, transcurrent, left-Iateral, tectonic displacements in the Badajoz-Córdoba Ductile Shear Belt have been estimated at ca. 200-300 km. Their regional implications in relation to the variscan emplacement of Allochthonous Complexes from NW Spain are discussed.