EVENTOS DE CISALHAMENTO E MINERALIZAÇÃO AURÍFERA NA REGIÃO NORDESTE DO QUADRILÁTERO FERRÍFERO: CONSIDERAÇÕES BASEADAS EM ANÁLISES U-PB DE RUTILO E TITANITA

Abstract

U-Pb analyses were carried out on rutile and titanite from sheared mafic volcanics and gneissesfrom northeastern Quadrilátero Ferrífero. Rutile growth is related to hydrothermal alteration andgold mineralization in the Nova Lima Group. Rutile analysis is 24% discordant and yield 207Pb/206Pb age of 2580 Ma whilst titanite in the gneiss is 3.5% discordant and yield 207Pb/206Pb age of2555 Ma. It can be concluded that a first episode of shearing and gold mineralization occurred duringthe Archean. This episode could not be precisely dated due to lead loss induced by Proterozoic events.