Petrology, petrofabrics, and structural geology of the Sierra de Outes — Muros Region (Prov. La Coruña, Spain)

The petrography and the structural geology of some parts of the ”Hercynian” orogene of western Galicia is discussed. The oldest rocks are metasediments and orthogneisses which have some relic-structures of an older orogeny. The ”Hercynian” migmatization gave rise to a large series of anatectic granite formations. Three ”Hercynian” phases of deformation, all with a WSW-ENE-directed stress-field, have been distinguished. Younger wrench-faults are originated by the same stress-field. Some fabric analyses show that the first two phases have a sub-vertical, NNW-SSE-striking schistosity, each with a horizontal B-axis, and that the third phase has a vertical N-S-striking cleavage with a vertical B’-axis. The migmatization took place after the first phase.