Characterization of Placer and Lode Gold Grains as an Exploration Tool in East-Central British Columbia (NTS 93A, 93B, 93G, 93H)
- Jim Mortensen, University of British Columbia
The compositions and shapes of placer gold grains, and the nature of microscopic mineral inclusions contained within them, can provide insights into the styles, and in some cases the precise locations, of lode sources from which the gold was derived. Such information therefore represents a valuable and relatively low-cost tool for guiding lode gold exploration in areas where placer gold is present for which lode sources have not yet been positively identified. We have developed an array of microchemical and imaging tools for characterizing the composition of placer gold and linking it with possible lode sources, as well as estimating the distance a population of placer gold grains have traveled from their source. We are applying these methods in a large portion of the Cariboo District in east-central BC, where several distinct styles of gold (and copper-gold) mineralization, including orogenic gold veins, gold-bearing mantos, sediment-hosted disseminated gold deposits, and copper-gold porphyries, occur and are being actively explored for by industry, and where placer gold deposits are widely developed.