Characterization of the Wager shear zone, Nunavut, Canada: Insights from microstructures and geochronology

The Wager shear zone is an ~450-km long zone of high strain hosted within Proterozoic and Archean rocks of the Rae domain in northwestern Hudson Bay, Nunavut. New field mapping and microstructural analyzes, combined with titanite and apatite geochronology, define the style, kinematics, and timing of Proterozoic ductile deformation. The results indicate that the Wager shear zone accommodated high-temperature deformation between ca. 1.75 and 1.74 Ga with post-kinematic cooling through apatite U-Pb closure (425-530 [degrees]C) at ca. 1705 Ma. These new data show that the Wager shear zone was last active later than inferred in previous work, at a time when the western Churchill Province was undergoing lithospheric delamination and exhumation following the terminal collisional events in the western portion of the Trans-Hudson Orogen. Key words: shear zone, titanite, apatite, U-Pb geochronology, Zr-in-titanite geothermometry, Trans-Hudson Orogen
1. Introduction The Trans-Hudson Orogen is a large and foundational orogen of the North American plate that formed during the amalgamation of the Nuna (Columbia) supercontinent, which subsequently broke up [...]