Descripción y resultados preliminares del plutón compuesto de San Xiao, Complejo de Cabo Ortegal (noroeste del Macizo Ibérico)

Abstract

The San Xiao composite pluton is a small body intruded in a metasedimentary formation of the Cabo Ortegal Complex upper units, the Cariño Gneisses. In spite of its size, it exhibits spectacular evidence of magma mingling processes. Based on the compositional features of the rocks and their relationships, we distinguish three different igneous units: mafic unit, felsic unit I and felsic unit II. Field evidence suggests that mingling processes occur between the first two units, whereas the third unit cuts them. Preliminary interpretation of geochemical data suggests that this pluton was formed in a mature volcanic arc, from different magmatic sources. This interpretation is compatible with previous models for the Cabo Ortegal upper units origin