Proposed Title 1: - Queen's University

and thrusting during the 1.94-1.92 Taltson-Thelon Orogen, producing tight to isoclinal
folds, ductile transposition and development of east-southeast-trending foliation superseded
by north-northwest-trending upright folds. This is consistent with F1, F2 and F3 type 2
interference fold pattern observed at the Ace-fay deposits (Fig. 2.7D). Ashton et al. (2007)
interpreted overprinting tight to isoclinal northeast-trending, predominantly southwestplunging
folds that formed during the 1.91-1.90 Ga metamorphic event of the Snowbird
Tectonic Zone (Fig. 2.15). These two major compressional orogens (Fig. 2.13D) likely
overprinted and obscured early ductile and brittle-ductile fabric associated with the
Arrowsmith Orogen.
Subsequent to a period of erosion that exposed the fault zones at shallower crustal
levels immediately after the Snowbird Tectonic Zone (Bethune et al., 2010), fault activity
changed from dominantly ductile-brittle to brittle deformation causing widespread U 4
uranium-rich brecciation along reactivated fault zones (Fig. 2.13E). The 1848±5 Ma U 4
uranium-brecciation stage is consistent with fault reactivation during tectonic shortening
and regional metamorphism of the Trans-Hudson Orogen or more likely post-peak
compressional uplift during terminal collision of the Taltson-Thelon Orogen. Reactivated
fault zones would have acted as high-permeability conduits that focus fluid flow into the
breccia system leading to hydrothermal alteration and deposition of the U 4 uranium
mineralization and Br 1 -Chl 7 -Src 3 -Hem 6 -Py 5 -Cpy 4
mineral assemblage (Fig. 2.8). The
Trans-Hudson Orogen, located east of the Beaverlodge area (Fig. 2.14), marks the
amalgation involving Wyoming, Slave, Churchill, Superior and Sask provinces into the
cratonic core of Laurentia (Hoffman, 1989; Ansdell, 2005). Ansdell et al. (1999) identified
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