Adam Fage

The Ice copper-gold deposit is located in the Carmacks copper belt, UTM zone 08V, 417935E, 6905900N, Yukon. First staked in the early 1970s, it is currently being explored by BC Gold Corporation of Vancouver, British Columbia. Exploration has focused on the eastern edge of a bulls-eye positive aeromagnetic anomaly, measuring roughly 1000 m by 700 m. The Carmacks copper belt contains economic porphyry-type copper type deposits, such as the Minto and the Carmacks Copper. This study is based on field mapping, petrography, ore microscopy, microprobe analyses and rock geochemistry. It reviews exploration history in the context of genetic models and the known geology of other deposits in the region.

The Ice surficial rocks studied so far contain malachite and other copper oxides in pores and fractures, probably previously occupied by sulphides. Small irregular particles of native silver are present. Disseminated magnetite, partially oxidized to hematite (martite) accounts for the relatively high magnetic susceptibility of the rocks. The low-grade copper is hosted within variably sheared and altered hornblende-biotite granodiorite phases of the early Jurassic Granite Mountain Batholith. Fabrics and recrystallized quartz veinlets suggest that hydrothermal mineralization preceded deformation. It is suggested that, as previously established for the Minto and Carmacks Copper, the Ice deposit formed in the Jurassic at considerable depth (> 5 km) in a porphyry copper system, and that tectonic deformation (ductile shearing) followed the main mineralization event. Exhumation and extensive weathering occurred in the Cenozoic.

The positive correlation of copper values with potassium and rubidium is compatible with a primary association of copper with potassic alteration in a porphyry system; the occurrence of remnants of iron and native silver in vugs occupied by copper oxides suggests that these were occupied by hypogene minerals. The preferred model envisages a porphyry system sheared into a tabular foliated granodiorite body; structural mapping and radiometric surveys could be useful exploration tools. It is possible that some of the oxide mineralization has been displaced from its hypogene source by migrating groundwaters during the Cenozoic, making it an exotic (displaced, secondary) copper deposit.ble bed, cosmogenic nuclides, till genesis, interglacial, Caledonia Phase.

Pages: 61
Supervisor: Marcos Zentilli