Field analyses reveal hydrothermal processes and mineralization in the Antas Norte ISCG deposit, indicating fluid evolution in the Archean to Paleoproterozoic era.
The Antas Norte mine, located in the southeastern portion of the Amazonian Craton within the Carajás Mineral Province, is hosted by mafic and felsic metavolcanic rocks that have undergone extensive hydrothermal alteration. Fieldwork and petrographic analyses reveal a hydrothermal sequence comprising sodic (albite), potassic (biotite + scapolite), calcic (amphibole + apatite), silicification (quartz), and propylitic (chlorite + epidote + calcite) assemblages. Mineralization, associated with calcic alteration, occurs in massive, brecciated bodies and vein networks, predominantly composed of chalcopyrite, pyrrhotite, and pyrite. The absence of iron oxides and dominance of iron sulfides classify Antas Norte as an Iron Sulfide Copper-Gold (ISCG) deposit, a subtype of the Iron Oxide Copper-Gold (IOCG) group. The deposit may represent a deeper and more reduced counterpart within the regional IOCG mineralization spectrum, similar to ilmenite-rich Iron Oxide-Apatite (IOA) systems.
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Hühn et al. (2025) studied this question.
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