The Paleoproterozoic Amer supergroup, Amer Fold Belt, Nunavut: stratigraphy, structure, correlations, and uranium metallogeny

The Amer Belt, hosting eleven informal formations of the supergroup, is proposed as type area for four regional Paleoproterozoic sequences (Ps1–Ps4) in central Rae Craton, western Churchill Province. ca. 1.9–1.865 Ga Snowbird orogeny (D P1 ) affected only Ps1–Ps3, whereas 1.87–1.81 Hudsonian P2 all four. Sequence Ps1 Ayagaq Lake formation (<2.3 quartzite) initiates schistose basal polymict orthoconglomerate unconformably overlying paleoweathered Neoarchean rocks. It transitions upward to lower Ps2 Resort formation: gossanous, recessive, graphitic, pyritic-metalliferous phyllite (Re–Os age: 2126 ± 24 Ma). conductors beneath <1.74 Thelon have been drilled unconformity-related uranium. Gradationally siliceous dolomitic marble (Aluminium River formation) completes Ps2. gradationally Ps3 either foliated calcareous tholeiitic basalt (Five Mile or grey (Three Lakes formation). These lateral equivalents host strong linear aeromagnetic markers. Oora feldspathic sandstone overlies Three and underlies upper Showing (interbedded arkose) whose two arkose members laterally continuous disseminated uraninite + magnetite forming Pristine sequence Ps4 molasse, deposited weakly deformed during D , comprises rhythmically interbedded, deep maroon pink green, feldspathic-lithic arenite, conglomerate, mudstone that overlie include clasts -deformed Ps1–Ps3 basement. detrital zircon (3.05–1.90 Ga) suggests local distal provenance from south Slave Cratons, Taltson–Thelon magmatic zone.