Factors controlling the formation and localization of reverse-offset unconformity-related uranium deposits along the Midwest Trend, Athabasca Basin, northern Saskatchewan********

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Uranium (U) mining is an important part of the mining industry in Canada and currently all the U production in Canada is from the Athabasca Basin in northern Saskatchewan. The U deposits in this basin are located near the unconformity between the basin and the basement, and are termed "unconformity-type" or "unconformity-related". Similar deposits are also developed elsewhere in Canada and other parts of the world. It has been recognized for a long time that all of the unconformity-related U deposits are associated with reactivated basement faults crosscutting the unconformity, but it has not been well understood why most of the basement faults are barren and only small portions of some of the reactivated basements are mineralized. Determining the factors that control U mineralization in reactivated basement faults is thus important for U exploration. The proposed research aims to decipher the ore-controlling factors through a detailed geological, geochemical and hydrodynamic study of the Midwest Trend (in NE Athabasca Basin), which hosts several known deposits and is actively explored for new U resources by Orano Canada, the industrial sponsor of this research project. The proposed research consists of six components: 1) three-dimensional (3D) geological modeling, 2) petrographic and paragenetic studies, 3) fluid temperature-pressure-composition characterization, 4) geochemical reaction path modeling, 5) fluid flow modeling, and 6) reactive mass transport modeling. The results will be used to evaluate the best conditions for fluid channelling and fluid-fluid and/or fluid-rock reaction leading to effective precipitation and accumulation of U ores. The research will help Orano and other exploration companies find more U deposits in the Athabasca Basin and other basins with similar geological conditions.