Great Slave Lake shear zone, NW Canada : mylonitic record of Early Proterozoic continental convergence, collision and indentation

Abstract

Great Slave Lake shear zone, in the NW Canadian Shield, is an excellent example of the kinematic, magmatic and thermal evolution of a crustal-scale shear zone associated with a collisional continental boundary. It is a 25 km wide corridor of granulite to lower greenschist facies mylonites and cataclastic fault rocks developed in the deep-seated parts of an Early Proterozoic (2.0–1.9 Ga) magmatic arc, constructed on the upper (Rae) plate at the contact between the Archean Slave and Rae continents. The rocks of Great Slave Lake shear zone, the Thelon magmatic arc and the Taltson magmatic zone are all components of the same magmatic arc, but their geological histories reflect different aspects of the continental interaction.