New Insights into the Wernecke Breccia iron oxide-copper-gold (± uranium) district, Yukon, Canada

CIM Vancouver 2006
Tim Baker, Derek Thorkelson,
Abstract At least 65 iron oxide-copper-gold ± uranium ± cobalt (IOCG) prospects are associated with a large-scale Proterozoic breccia system in north-central Yukon Territory, Canada. The breccia system, known as Wernecke Breccia, consists of numerous individual breccia bodies that occur in areas underlain by the Early Proterozoic Wernecke Supergroup, an approximately 13 km-thick deformed and weakly metamorphosed sequence of sedimentary rocks. The IOCG mineralisation occurs as multiple episodes of veining and disseminations within and peripheral to the breccia bodies. Brecciation and mineralisation are associated with extensive sodic and potassic metasomatic alteration overprinted by pervasive carbonate alteration. Wernecke Breccia is spatially associated with regional- and local-scale faults and breccia bodies and mineralisation formed in weak and/or permeable regions during syn- to post-deformational expansion of over-pressured fluids. The scale of brecciation in this area is similar to that in other large-scale breccia provinces that host significant mineralisation, e.g. Cloncurry district, Australia (Ernest Henry deposit: 167 Mt @ 1.1% Cu, 0.54 g/t Au), Gawler district, Australia (Olympic Dam deposit: >600 Mt @ 1.8% Cu, 0.5 kg/t U3O8, 0.5 g/t Au, 3.6 g/t Ag), Punta del Cobre district, Chile (Candelaria deposit: 470 Mt @ 0.95% Cu, 0.22 g/t Au, 3.1 g/t Ag), however, limited exploration has been carried out in the Wernecke Breccias and their mineral potential remains largely unknown.
Keywords: breccia, Yukon, iron oxide-copper-gold, Copper, Wernecke Breccia, Proterozoic, IOCG
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