Geology, mineralogy, and geochemistry of the Kelly Lake nickel-copper-platinum group element deposit, Sudbury, Ontario

The Kelly Lake Ni-Cu-PGE deposit, Sudbury, comprises four ore bodies (710, 720, 725, and 740), which were first identified in 1997 and contain a published 10.5 million tonnes of ore at 1.77% Ni, 1.34% Cu, and 3.6 g/tonne Pt+Pd+Au. The purpose of this study has been to characterize the geology, ore textures, mineralogy, and geochemistry of the Kelly Lake ore bodies in an effort to elucidate on the sulfide mineralizing processes that may have been involved in the formation of offset-style ore deposits.; In general, the ore zones of the Kelly Lake deposit comprise massive Cu-poor cores surrounded by Cu-rich disseminated margins. There is a continuum between Cu-poor and Cu-rich sulfides, consistent with fractional crystallization of monosulfide solid solution (MSS) within the Kelly Lake ores, and metal tenors (metal in 100% sulfides) increase with increasing fractionation. All ore types have higher Cu and PPGE relative to Ni and IPGE, but disseminated ores are more fractionated than massive ores and commonly have higher metal tenors. Disseminated ores exhibit strong correlations between Ni and IPGE, whereas massive ores exhibit strong correlations between Cu and PPGE.; Several processes may have contributed to the sulfide zonation observed at Kelly Lake, including: (1) separation of immiscible Cu-rich and Cu-poor sulfide liquids, (2) fractional crystallization of MSS, (3) filtration processes (gravity and/or capillary), and (4) post-magmatic metamorphic and hydrothermal mobilization. However, the distribution of ore types, textures, and geochemical data suggest that the most important process involved in producing the range of Cu-rich to Cu-poor ores at Kelly Lake was fractional crystallization of MSS. (Abstract shortened by UMI.)...