Abstract: Gold mineralization has been identified on the foliated margins of Paleozoic gabbroic intrusions, where a protracted series of structural preparation events has enhanced rock permeability. Rheological contrasts between these mafic rocks and amphibolite facies metasedimentary hosts have resulted in variable foliation development, especially at margins of mafic bodies. Initial foliation development centred on granitoid material in magmatic intrusion breccia, and was enhanced by syn-metamorphic biotite formation. Early mineralized quartz vein development occurred under greenschist facies conditions during and/or after regional Mesozoic thrust stacking of kilometre scale rock slabs. Initial vein emplacement was largely controlled by the foliation in mafic gneiss, and minor chloritic alteration and later hydrothermal generations cut across all structures. Gold mineralization involved only minor introduction of As, Sb, and S, and the hosting quartzite has higher As, Sb, and S content than most mineralized veins. Au is accompanied by elevated Bi, Mo, and Te in quartz veins.

Authors: MacKenzie, D., Craw, D., Brodie, C. and Fleming, A.

Citation: MacKenzie, D., Craw, D., Brodie, C. and Fleming, A., 2013. Foliation development and hydrothermal gold emplacement in metagabbroic rocks, central Yukon, Canada. In: Yukon Exploration and Geology 2012, K.E. MacFarlane, M.G. Nordling and P.J. Sack (eds.), Yukon Geological Survey, p. 47-64.

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