Geology and Hydrothermal Evolution of the Antas North Iron Sulfide–Copper–Gold (ISCG) Deposit in the Carajás Mineral Province

The Antas North mine, located in the southeastern Amazonian Craton within the Carajás Mineral Province, is hosted by mafic and felsic metavolcanic rocks that have undergone extensive hydrothermal alteration. Field and petrographic data reveal a hydrothermal sequence comprising sodic (albite), potassic (biotite + scapolite), calcic (amphibole + apatite), silicification (quartz), and propylitic (chlorite + epidote + calcite) assemblages. Copper–gold mineralization, spatially associated with calcic alteration, occurs as massive sulfide lenses, breccia zones, and vein networks dominated by chalcopyrite, pyrrhotite, and pyrite. The absence of magnetite/hematite and the dominance of sulfides and ilmenite classify Antas North as an Iron Sulfide–Copper–Gold (ISCG) system, representing a reduced endmember within the broader IOCG spectrum. New U–Pb titanite geochronology yields two concordant age populations at ca. 2476.6 ± 15.9 Ma Ga and 2162.9 ± 28.1 Ma Ga, recording a late Archean mineralizing stage and subsequent Paleoproterozoic reactivation during the Transamazonian orogeny. These ages parallel the multistage evolution recognized in other Carajás IOCG deposits, where copper–gold-related mineralization was repeatedly overprinted by later tectono-hydrothermal events. The reduced character of Antas North, marked by ilmenite and sulfide dominance with scarce magnetite, demonstrates that reduced IOCG styles were already established in the Neoarchean–Paleoproterozoic transition and underscores the diversity of mineralizing processes within the Carajás IOCG–IOA spectrum.