Metamorphism in Neoarchean Granite-Greenstone Belts: Insights from the Link between Elu and Hope Bay Belts (∼2.7 Ga), Northeastern Slave Craton

Abstract

AbstractThe Elu Link in the northeast Bathurst Block of the Slave Craton, Canada, is composed of variably D1–D3-deformed, low- to medium-grade supracrustal and intrusive rocks connecting the Neoarchean Hope Bay and Elu granite-greenstone belts (∼2.7 Ga). Textural observations and pseudosection modeling show that the primary metamorphic reactions in the supracrustal rocks derived from D1-assisted hydrothermal alteration in albite-epidote hornfels-facies to greenschist-facies conditions. This was followed by one main cycle of prograde, peak, and retrograde metamorphism that variably accompanied D1 and D2 events along a clockwise pressure-temperature (PT) path. The pseudosection for a garnet-bearing orthogneiss whose protolith emplacement occurred before peak metamorphism indicates maximum upper-amphibolite conditions of 6.7 kbar and 710°C, reached during D2 deformation. Thereafter, the orthogneiss followed a counterclockwise PT path showing an increase in pressure (up to 8.7 kbar) during the late stages of ...