Structural evolution and related implications for uranium mineralization in the Patterson Lake corridor, southwestern Athabasca Basin, Saskatchewan, Canada

The Patterson Lake corridor is situated along the SW margin of the Athabasca Basin and contains several basement-hosted uranium deposits and prospects. Drill core investigations during this study have determined that granite, granodiorite, mafic and alkali intrusive basement rocks are entrained in a deep-seated NE-striking subvertical heterogeneous high-strain zone defined by anastomosing ductile to semi-brittle shears and brittle faults. The earliest phases of ductile deformation (D1/D2), linked with Taltson (1.94–1.92 Ga) orogenesis, involved interference between early fold sets (F1/F2) and development of an associated ductile transposition foliation (S1/S2). During subsequent Snowbird (c. 1.91–1.90 Ga) tectonism, this composite foliation was re-folded (D3) by NE-trending buckle-style folds (F3), including a regional fold centred on the Clearwater aeromagnetic high. In continuum with D3, a network of dextral-reverse chloritic-graphitic shears, with C–S geometry, formed initially (D4a) and progressed to more discrete, spaced semi-brittle structures (D4b; c. 1.900–1.819 Ga). Basin development (D5a;