Structural characterisation and geochronological constraints on the Wager shear zone, northwestern Hudson Bay, Nunavut ...

• Main Author: Therriault, Isabelle
• Format: Text
• Language: English
• Published: University of British Columbia 2019
• Subjects: Hudson Bay; Nunavut
• Online Access: https://dx.doi.org/10.14288/1.0378539; https://doi.library.ubc.ca/10.14288/1.0378539

The Proterozoic Wager shear zone (WSZ) is a major zone of high strain located on the northwestern coast of Hudson Bay, Nunavut. New geological mapping was conducted during the summer of 2017 to characterise the timing, duration and kinematics of the deformation recorded by the WSZ and to interpret this new information in the regional tectonic context. At the outcrop scale, the shear zone is marked by a steep, east-west striking mylonitic foliation and a sub-horizontal mineral-stretching lineation and displays abundant dextral shear-sense indicators. Fieldwork outlined boundaries of an apparent strain gradient within the shear zone that generally correlates with microstructural observations. Paleopiezometry investigations of feldspar suggest that deformation occurred in the dislocation creep regime for that phase, near the transition into the diffusion creep field. It also revealed that strain rates recorded by the WSZ are consistent with those from other ductile high-strain zones. Zr-in-titanite thermometry ...