Mineralogy and pathfinder element geochemical behaviour in the G.R. Halli gold deposit, Chitradurga Schist Belt, India

摘要

Gold itself can invariably be used as a pathfinder element in geochemical exploration. Gold mineralisation at G. R. Halli is hosted by sheared sulphide-rich quartz veins located at the lithological contacts. Intensely sheared, brecciated and mylonitised zones are found to be the ideal locci here for gold mineralisation. Mineralisation comprises of disseminations, stringers, and fracture fillings of pyrite, arsenopyrite, galena, sphalerite, chalcopyrite and rarely cobaltite. Gold and the pathfinder elements Cu, Co, Cd, Ag, As, Ni, Pb, Zn, Mn were analysed to understand the geochemistry of the deposit. Pb, As, Co, Zn and Ag correlate positively with gold, which is also corroborated mineralogically by EMPA and ore microscopic studies. Textural relationships suggest the genetic sequence of minerals to be: arsenopyrite-galena-sphalerite-chalcopyrite-pyrite-cobaltite. Field relationships and data suggest that G. R. Halli gold deposit has been formed by remobilisation and epigenetic process during regional metamorphism.