Evidencias metamórficas y estructurales de extensión tardiorogénica hercinica: el ejemplo del Domo Gneisico del Tormes (NO Salamanca)

Abstract

The tectonothermal Variscan evolution of the Tormes Gneiss Dome is controlled by a subhorizontal ductile shear zone of crustal scale and extensional characteristics, that induced a quick exhumation of the deep parts of the metamorphic complex during crustal thinning. The shearing affected a broad band of metamorphic rocks but, as the temperature decreased, became progressively concentrated in a low-grade ductile detachment that separates two distinct units, characterized by their lithology and different tectonothermal evolution. Kinematic indicators in non-coaxial fabrics show a displacement of the hangingw all to the SE, i.e., parallel to the trend of the foldbelt. The subhorizontal shearing is related to the extensional collapse of the variscan crust, previously thickened during the collision tectonics