Sumario de la mineralización metalífera y su genesis en Galicia occidental (España)

The mineralizations of Fe, Cu, Li, Sn, W in W. Galicia are discussed. Sulphidic mineralization of Fe and Cu is exemplified by a description of the mine of Fornás (SE. of Santiago de Compostela). Field and laboratory data (including geothermometry of the phases of the Fe-Zn-S system) suggest that the deposit has been subjected to regional metamorphism of amphibolite facies grade. Li-bearing pegmatites (with spodumene, petalite, montebrasite, beryl, cassiterite, columbite and alteration products) are locally rather common in the area. It is argued that they have intruded as masses of silicate melt along faults. Cassiterite and wolframite are found in quartz veins with pockets of alcaline feldspar, suggesting a genetic relationship with the pegmatitic rocks. The mineralized dykes and veins are related to the hercynian two-mica granites. In Portugal similar mineralizations are considered to be connected with post-tectonic biotite granites. Alternative explanations of this apparent discrepancy are given. A primera vista la mineralización en Galicia no parece muy complicada. Se presentan dos tipos principales relacionados especialmente con dos unidades petrológicas: 1) los yacimientos de sulfuros de hierro y cobre asociados con el complejo máfico (el lopolito) y, 2) la mineralización de litio, estaño y wolframio asociada con los granitos