New mapping and initial structural characterization of the Wager shear zone, northwestern Hudson Bay, Nunavut

New geological mapping was conducted during the summer of 2017 along the inferred Paleoproterozoic Wager shear zone (WSZ), located on the northwestern coast of Hudson Bay, Nunavut. This work is the basis for a project that aims to better constrain the timing, duration and kinematics of the deformational events preserved by the WSZ, and to interpret these events in a regional context. Fieldwork consisted of daily traverses across the shear zone, during which lithological and structural data were recorded, and samples were collected for petrographic, microstructural and geochronological analyses. At the outcrop scale, the shear zone is characterized by a steep, eastor west-trending mylonitic foliation and a subhorizontal mineral-stretching lineation with abundant dextral shear-sense indicators. A broad strain gradient across the southern boundary of the WSZ is up to 2–3 km wide, whereas the northern boundary appears to be more abrupt, generally less than 250 m wide. Rocks outside the shear zone preserve evidence of earlier, largely sinistral, deformation. Detailed analytical work is now underway to help unravel the complex structural history of the area and investigate the potential relationship between the WSZ and Paleoproterozoic (and possibly older) regional tectonic events.