Early Proterozoic metamorphism at The Granites gold mine, Northern Territory: implications for the timing of fluid production in high- temperature, low-pressure terranes

Abstract

Gold mineralization at The Granites, occurs in a sequence of amphibolite facies pelitic and semipelitic schists forming part of the Early Proterozoic Granites-Tanami block. Cummingtonite and hornblende schists occur in alteration assemblages surrounding mineralized calcite veins in the pelitic and semipelitic schists, as well as in the footwall and host gold lodes, and are associated with high-temperature metasomatic addition of Ca and depletion of K. The mobilization of the significant volumes of fluid necessary for metasomatism and associated mineralization during convergent deformation is modeled as a consequence of the lithospheric-scale deformation geometry appropriate for the generatio..