GRANITIC PEGMATITE- AND LEUCOGRANITE-HOSTED URANIUM MINERALIZATION ADJACENT TO THE ATHABASCA BASIN, SASKATCHEWAN, CANADA: A DIFFERENT TARGET FOR URANIUM EXPLORATION
The magmatic-hosted deposits (Fraser Lakes Zones A and B) are in NE-plunging regional fold noses adjacent to a 5 km long folded EM conductor (i.e. graphitic pelitic gneisses). The more prospective Zone B sits within an antiformal fold nose, from which several drill holes have intersected multiple intervals of uranium and/or thorium mineralization (up to 0.183% U3O8 over 1.0 m in drill core). The zones are cross-cut by a number of E-W-, NNE-, and NNW-trending structures. Associated with the uranium are thorium and LREE mineralization with elevated amounts of pathfinder elements including Co, Cu, Mo, Ni, Pb, V, and Zn.
Drill core observations revealed the existence of multiple generations of granitic pegmatites, including mineralized (generally subcordant to gneissosity, and believed to be syndeformational) and non-mineralized (discordant to gneissosity, and probably post-tectonic) varieties, with some of the pegmatites showing compositional zoning due to igneous AFC processes.
While this is a magmatic-hosted U-Th deposit, the presence of clay alteration and structural features in Zone B drill core similar to that of basement-hosted unconformity uranium deposits (e.g. Millennium, P-Patch, Eagle Point, and McArthur River Zone 2) raises the possibility that altered remobilized parts of the Fraser Lakes zones formed at the same time as unconformity-type mineralization in the Athabasca Basin. This project will integrate field observations and geological, geochemical, and geophysical datasets so to develop a metallogenetic model for the Fraser Lakes deposit, and clarify its relationship with the rich uranium deposits in the Athabasca Basin (e.g. U protore).