The Fe-As-Cu-(Bi-Au) ores of Chinipi (Central Spanish Pyrenees)

摘要

The sulphidic ore deposit of Chinipi, hosted by early Carboniferous limestones, is related to a Hercynian thrust system affecting Devonian lutites, Carboniferous limestones and Permian red beds. Microscopic and XRD studies identify pyrite and arsenopyrite as the main ore minerals. Chalcopyrite, tennantite, pyrrhotite, native bismuth, bismuthinite, galenobismutite, covellite, proustite, kobellite and enargite are also present. The ores show an important cataclastic texture as a result of the intense deformation. According to arsenopyrite geothermometry, vein formation occurred at around 475°to 550℃. Stable isotopic study indicates that the mineralizing fluids had a strong magmatic influence. This ore deposit has some peculiarities different to other veins in the Pyrenees: field evidence support the idea that the Chinipi vein was formed during the late-Hercynian times, related to volcanism episodes, which marked the transition between the Hercynian and Alpine orogenies.