The Papagaios Gold Deposit: Record of Multiple Hydrothermal Mineralization Events in the Pitangui Greenstone Belt, Brazil

Abstract The Papagaios gold deposit in the Pitangui greenstone belt, Brazil, exhibits a complex metallogenic evolution characterized by multiple hydrothermal events. This study presents the first comprehensive characterization of its geology, petrography, lithogeochemistry, and mineral chemistry to elucidate the gold mineralization evolution. The mineralization is hosted in granitoids and a metavolcanic-sedimentary sequence metamorphosed to amphibolite facies (~630°C, garnet-biotite geothermobarometry) and is structurally controlled by east-northeast to west-southwest shear zones. Four hydrothermal stages have been identified based on their relationship to the Sn foliation. The pre-Sn stage features Mn-rich dolomite and talc-dolomite-chlorite-actinolite veins, with gold-bearing pyrite disseminated in metabasalts and volcaniclastic rocks, suggesting a possible Archean volcanic-hosted massive sulfide-(VHMS)-like system. Syn-Sn mineralization is hosted in silicified zones with carbonate-chlorite halos, where free gold is associated with sulfide assemblages. Chlorite chemistry points to formation temperatures of 180° to 475°C under oxidizing conditions, while lithogeochemistry reveals an Au-Cu-Pb-Zn signature. Syn- to late-Sn Na-Ca alteration halos envelop Neoarchean granitic intrusions, suggesting a high-temperature and saline magmatic-hydrothermal process consistent with intrusion-related systems. The post-Sn stage shows propylitic and phyllic alteration with Au-Fe-As–rich sulfide-oxide assemblages formed between 190° and 390°C under reducing conditions, according to chlorite chemistry. While tourmaline chemistry suggests saline fluids, and white mica points to formation pressures around 2 kbar. This stage may reflect a late Neoarchean magmatic-hydrothermal fluid release or a Paleoproterozoic overprint. The multistage evolution of the Papagaios deposit is distinct from other mineral deposits within the Pitangui greenstone belt and Quadrilátero Ferrífero metallogenic scenario, and implies an interplay of VHMS, orogenic, and intrusionrelated gold systems.