Paleoproterozoic structural evolution of the southwestern margin of the Rae craton, Northwest Territories

The structural and thermal evolution of the southwestern margin of the Rae craton, exposed in the Nonacho Lake area (NLA) of the southeastern Northwest Territories, is poorly understood due to a paucity of previous geological mapping and study. Detailed bedrock mapping, microstructural analysis, U-Pb zircon geochronology, U-Pb titanite and apatite petrochronology, and 40Ar/39Ar thermochronology are used to constrain the kinematics and timing of deformation of major-domain bounding structures in the NLA, as well as to document the exhumation history across the southwestern Rae craton. The integration of microstructural, geochronological, and thermochronological constraints revealed two major periods of deformation localized along shear zones in the NLA at ca. 2290–2160 Ma and ca. 1830–1790 Ma, which are temporally associated with the exhumation of NLA domains. The two periods of structurally-controlled exhumation are broadly coincident with the late- to post-Arrowsmith Orogeny and the late stages of the Trans-Hudson Orogeny.