UBC Undergraduate Research

Geology, Alteration, and Mineralization of the Sugar Gold Prospect, Yukon Territory, Canada Bartlett, Stephen

Abstract

The Sugar gold prospect, located 20 km southeast of the Coffee gold deposits and 10 km northwest of the Casino Cu-Au-Mo deposit in the Yukon Territory, is hosted in the mid- Cretaceous Dawson Range batholith. Sugar forms a part of a belt of gold mineralization within the Dawson Range and as such a study of its lithology, alteration, and mineralization offers important information for metallogeny in the Yukon, Canada. Three mappable sub-units are recognized in the field area: a biotite hornblende quartz monzodiorite; a K-feldspar phyric hornblende biotite syenogranite; and a biotite hornblende diorite. These plutonic rocks bearing continental-arc geochemical signatures are cut by steep, west to northwest-striking andesite dikes of unknown age which themselves bear continental-arc geochemical signatures. Altered and mineralized zones coincide with fault-fracture zones that are parallel and proximal to dikes and their margins. Alteration is characterized by an early phase of calc-sodic (albite-amphibole) and potassic (pervasive biotite, fracture-controlled K-feldspar, and localized albite-biotite) alteration and a later phase of silica and sericite alteration. Gold mineralization is associated with disseminated sulphides proximal to zones of silicification and sericitization with variably sheared veins of quartz-carbonate-arsenopyrite ± pyrite ± freibergite ± stibnite ± sphalerite. Late chalcedonic quartz-carbonate and ferroan carbonate veins represent the lowest temperature expression of the hydrothermal system.

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Attribution-NonCommercial-NoDerivatives 4.0 International