Overview of Brine-Hosted Lithium Mineral Resources, Distribution, and Genesis in the Western Canada Sedimentary Basin

Résumé fourni par la source

Abstract Saline brines from sedimentary basins could play a key role in providing the Li required for the energy transition. In the Western Canada Sedimentary Basin, economic (>75 mg/L) Li concentrations have been discovered in brines of Late Devonian-aged strata, specifically the Leduc, Nisku, and Swan Hills formations of Alberta and the Duperow Formation of Saskatchewan. Through industry activity, 75.9 M tonnes Inferred, 14.9 M tonnes Indicated, and 7.2 M tonnes Measured Li carbonate equivalent mineral resources, and Probable and Proven mineral reserves of 997,000 tonnes LCE and 141,000 tonnes LCE, respectively, have been identified. However, much of the exploration has primarily relied on historical brine data. Therefore, other prospective Li targets may have yet to be discovered, requiring the development of a deposit model to guide exploration to new areas. A key requirement for developing such a model is identifying the Li source. This work surveys the occurrences and distribution of Li in the Western Canada Sedimentary Basin, provides a compilation of the first Li-brine database and mineral resource estimates, discusses the implications for shared pore space policy, and examines hypotheses for the Li source. Seawater evaporation, evaporite dissolution, and contributions from the Precambrian basement have each been proposed as key factors in generating Li-rich brines in the Western Canada Sedimentary Basin, however, based on geochemical and isotopic evidence, as well as findings from other basins, we advocate for water–rock interactions with Li-rich shales. Other factors, such as dolomitization, clay transformations, evaporation, lithology, and the depositional environment, may also play a role. Understanding the genesis of Li-rich brines and developing a deposit model is crucial for guiding future exploration in sedimentary basins. A key issue for new pore space users in sedimentary basins, which includes lithium, helium, geothermal energy, and carbon sequestration, is sharing of the pore space. Issues may arise as competition for pore space grows, especially in areas where activities can overlap, necessitating that the development of established and emerging resources be guided by informed policy to ensure all stakeholders benefit. Basinal brine-hosted Li has the potential to be a significant new source of Li on a global scale and provide a greener source of a critical metal required for the energy transition, with western Canada well positioned to play an important role in this emerging field.

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