English (USA)

PRESERVAÇÃO DE MINERALIZAÇÃO VHMS NEOARQUEANA DURANTE METAMORFISMO REGIONAL A 2,08 Ga NO NORTE DO CRÁTON DO SÃO FRANCISCO: EVIDÊNCIAS DE GEOCRONOLOGIA U–Pb EM TITANITA

Resumen

The Fazenda Coqueiro volcanic-hosted massive sulfide (VHMS) deposit, located in the Mundo Novo greenstone belt, northern São Francisco Craton, represents Neoarchean base-metal mineralization subsequently overprinted by Rhyacian-Orosirian regional metamorphism. Although the timing of mineralization has been previously constrained by Pb–Pb isotopic data, the extent to which this metamorphic event modified the primary isotopic and genetic signature of the mineral system remains unresolved. This study presents new U–Pb geochronological data from metamorphic titanite in the ore-hosting metavolcanic sequence to constrain the timing and effects of regional metamorphism. Titanite grains yield a concordant age of 2086 ± 58 Ma, interpreted as the timing of greenschist- to amphibolite-facies metamorphism. In contrast, previously established Pb–Pb ages of the sulfide mineralization preserve Neoarchean isotopic signatures, with no evidence of isotopic resetting. The persistence of Archean Pb isotopic compositions despite Rhyacian-Orosirian metamorphism implies limited Pb mobility during recrystallization and attests to the isotopic robustness of the primary mineral system. These results demonstrate clear temporal decoupling between Neoarchean mineralization and subsequent metamorphism, establishing the Fazenda Coqueiro deposit as a well-preserved Neoarchean ore system within a reworked Paleoproterozoic terrane. In this context, the findings also highlight the long-term preservation potential of primary metallogenic signatures in metamorphosed greenstone belts and carry significant implications for mineral exploration in ancient cratonic domains.