Mafic and related complexes in Galicia: an excursion guide

In Galicia occur several polymetamorphic complexes that contain mafic and ultramafic rocks. Mafic volcanics and gabbros are situated in or near the complexes. An episode of metamorphism and granitization encompassed the generation of the volcanics and gabbros. Gravity surveys revealed the existence of deep roots below polymetamorphic complexes. Geochronological investigations yielded Palaeozoic ages from about 500 Ma for the generation of ultramafic rocks and calcalkaline granite series, till ages of around 300 Ma for postkinematic alkaline and calcalkaline granites. A model involving mantle-plume diapirism and rejuvenation of the lower crust is proposed for the Early Palaeozoic evolution of the continental lithosphere of Galicia. An excursion route is given, leading along 22 exposures of mostly mafic and ultramafic rocks, to be visited in 4 1/2 days.