Some examples of orthogneisses in Central Galicia

This paper put out the non-existence of an orthogneissic and migmatitic Precambrian socle in Central Galicia (Viana del Bollo region), an idea that had been held by different authors. The orthogneisses have been considered either similar to the formation of ‘Olio de Sapo’ or parent materials. The igneous origin of these gneisses is established, being intrusive in both ‘Olio de Sapo’ and in series with a probably Lower Cambrian age. Their ages and geometry are discussed and some correlations have been attempted with somewhat similar formations in the Iberian peninsula and in the Armorican Massif, carrying out the usefulness of detailed studies of these massifs to a chain scale.