The Sossego iron oxide Cu-Au deposit, Carajas, Brazil

摘要

The Sossego iron oxide Cu-Au deposit (50°05'W, 6°25'S) is hosted in intensely sodium(-calcium) metasomatized Archean volcanic and intrusive rocks. The Cu-Au ore is constituted by chalcopyrite, magnetite, minor pyrite, and trace molybdenite. Alteration minerals closely associated with chalcopyrite include amphibole, epidote, apatite, calcite, quartz, and locally biotite. Stable isotope data suggest that both non-magmatic and magmatic fluids participated in the Sossego hydrothermal system. Disturbed ~(40)Ar/~(39)Ar spectra of ore-related amphibole indicate a minimum alteration age of 2.2-2.3 Ga.