Seismic anisotropy of upper mantle-lower continental crust rocks in Cabo Ortegal (NW Spain) from crystallographic preferred orientation (CPO) patterns

Resumen

The development of crystallographic preferred orientation (CPO) in rocks as a consequence of deformation processes at high pressure and high temperature conditions is one of the sources of anisotropy in the propagation of seismic waves presently observed in deep seismic profiles of rocks in the lower crust and upper mantle. The CPO of 8 rock-forming minerals measured using electron backscattered diffraction (EBSD) is compared with direct measurement of the propagation of seismic waves at high pressure in 5 rock specimens (felsic gneiss, eclogite, mafic granulite, metabasite and pyroxenite) representing the transition from the upper mantle to the lower crust in the Cabo Ortegal Complex.