Paleoproterozoic (1.75 Ma) Granitoid Rocks and Uranium Mineralization in the Baker Lake -- Thelon Basin region, Nunavut

The Nueltin suite is comprised of the Nueltin granite, Pitz Formation rhyolite and related basaltic dykes. Despite the extensive range of emplacement, petrographic and geochemical analysis show that all Nueltin suite components are feldspar-phyric, strongly potassic, Fe-rich and highly fractionated, with enrichment in rare earth elements, except for strongly depleted Eu. Overall, the Nueltin suite shares strong affinity with anorogenic (A-type) igneous rocks, with an interpreted petrogenetic model of crustal melting due to ponding of basaltic melt in the lower crust within an extensional regime. Fractionation is likely responsible for enrichment of U, Th and REE. Significant U mineralization, located in the Kiggavik area, is associated with the Lone Gull granite, a geologically complex granite. The presence of secondary uranium mineralization in association with Paleoproterozoic Nueltin igneous rocks implicate the suite as prospective for exploration.