Detailed structural studies, Gibson Lake-Cross Bay-MacQuoid Lake area, Northwest Territories (Kivalliq region, Nunavut)

The Gibson Lake-Cross Bay-MacQuoid Lake area comprises a multiply deformed Archean terrane, tectonothermally reworked in the Paleoproterozoic. Multiple foliations in the western volcanic belt illustrate that the regional foliation is a second generation feature (S2), formed by transposition of layering and a layer-parallel foliation (S1). The S2 appears to have developed at ca. 2.68 Ga. Two subsequent generations of folds modified the S2 during the Paleoproterozoic. South-plunging F3 folds are restricted to the Cross Bay complex, whereas east- northeast-trending, F4 folds control much of the map pattern in the volcanic belt and southeastern part of the Cross Bay complex. The complex is bounded to the south by the Big lake shear zone, a 50 km long, dextral, strike- slip structure. The main phase of deformation and metamorphism in the shear zone is Paleoproterozoic, and its western segment is stitched by a late-stage (possibly ca. 1.83 Ga) granite.