Genesis of hydrothermal gold deposits

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About 20% of the world's cumulative gold production has come from orogenic gold deposits formed from Archean to throughout Phanerozoic. Although their formation is widely recognized as having resulted from the interaction of hydrothermal fluids with country rocks during the late stages of orogenic cycles, the sources of the ore-forming fluids are still poorly constrained. Various models have been proposed for the origin of fluids, including metamorphic, mantle devolatilization, magmatic and meteoric. This research program proposes (1) to evaluate the role of magmatic versus metamorphic fluids in the genesis of orogenic gold deposits and (2) to develop more refined genetic models. Such models will aid in identifying more prospective mineralized zones, thus improving the odds of success for global gold exploration.  This objective will be achieved by studying the generation and composition of magmatic and metamorphic fluids in various Archean and Phanerozoic belts hosting orogenic gold deposits. The research will focus on investigating the fluids within (a) granites that were emplaced coevally with gold mineralization in the Val d'Or district, Canada, and (b) metamorphic rocks from the Otago-Alpine Schists, New Zealand, where there is a lack of magmatism. This research program will involve integrated field and laboratory investigations that are key to the training of highly qualified personnel for both academia and industry. The results are also expecting to lead to the development of novel techniques for analyzing single fluid inclusions and will be pioneering the direct identification of the trace-element composition  of metamorphic fluids in greenschist- and amphibolite-facies metamorphic rocks.