Grant: Discovery Grants Program - Individual

Many economically important mineral deposits are formed by the circulation of fluids in sedimentary basins, such as the Athabasca Basin in north-central Canada that hosts a number of world-class uranium deposits. It is important to determine the factors that controlled the formation of such deposits to seek new ones. In my previous NSERC Discovery Grant term, significant progress has been made in understanding the source, transport and precipitation mechanisms of the ore-forming materials in the Athabasca Basin. It was discovered that most of the uranium in the ores was extracted from sediments in the basin, transported by basinal brines that were driven by rock deformation and thermal convection, channeled along faults rooted in the basement, and precipitated by reacting with reducing gases derived from deep sources. While these findings have important implications for uranium exploration, more work is required in order to narrow down potential exploration targets. Since there are numerous faults in the basement and only some of them host uranium deposits, it is of great interest to determine which types of faults are more likely to be mineralized. Furthermore, within the basement faults that are known to host uranium deposits, only certain segments of the faults are mineralized, and it is important to understand what kind of locations in these faults are favorable for mineralization. The proposed research aims to address these questions by examining three hypotheses: 1) structures near the unconformity (shallow) that are connected with regional-scale faults (deep) are more likely to be episodically reactivated, thus more favorable for fluid flow and mineralization, than structures without such connections; 2) structures that facilitated both ore-forming fluid flow (hydrodynamic) and fluid-fluid mixing and fluid-rock reaction (geochemical) are more likely to be mineralized than those without such a combination; and 3) the connectivity between major paths of fluid (channeling) and potential sites of mineralization (trapping), with balanced replenishment of reactants, is critical for mineralization. These hypotheses will be examined through geological and geochemical comparison between selected ore-hosting and barren structures, and tested by numerical simulation of fluid flow and chemical reactions (reactive transport modeling) involving different scenarios of fault connectivity and combinations of hydrodynamic and geochemical processes. The research results will help mining companies establish more effective exploration models to discover more uranium and potentially other critical metals resources, including lithium, rare earth elements, cobalt and nickel that are associated with uranium mineralization, in the Athabasca Basin. This is important for maintaining Canada's position as one of the top uranium producing countries in the world and for supporting the mining industry which plays a critical role in Saskatchewan's economy.