Distribución de la deformación en granitoides sincinemáticos intruidos en condiciones transpresivas (Sanabria, Zona Centro-Ibérica, Macizo Ibérico)

Resumen

The Sanabria Lake plutons, located in the Central Iberian Zone of the Iberian Massif, intruded in a dextral strike-slip fault bridge under transpressive conditions. The deformed zone underwent a strain partitioning process, so that large folded domains and narrow shear zones were developed coevally. The microstructural study of the granitoids shows that the shear zones concentrate a variable degree of solid state deformation at high and medium temperatures, whereas the folded areas preserve microstructural evidences of magmatic and submagmatic flow at high temperatures, too. The most common fabric in these folded areas is defined by two sets of conjugate planes, composed by aligned crystals of plagioclase and biotite, which are bisected by the flow foliation. These conjugate bands represent an incipient phase of the strain localization process that involves strain weakening, migration of the late-magmatic melts and enhancement of the shear zones.