Metamorphic petrology of the Precambrian basement of Devon Island, Nunavut, Canada
University of New Brunswick
Devon Island, making up part of the Arctic Archipelago, is located in Nunavut, Canada. The northernmost extension of the Canadian Shield is seen to outcrop along the coast of Devon Island. The crystalline basement is composed of granites and gneisses which have undergone granulite facies metamorphism. Much of the island is unconformably overlain by approximately 1800 m of sedimentary rocks. Three main rock types have been identified from the field area: gneisses, granitoids, and mafic to ultramafics. To further classify the rocks, the gneisses have been sub-divided into three major lithologies: quartzofeldspathic gneiss, biotite-homblende gneiss, and gamet-cordierite gneiss. Petrological analyses yield peak metamorphic temperatures in the range of 700°C and 800°C. A lower temperature range was also determined, 400°C to 600°C , which corresponds to retrogressive events that were initiated upon uplift of the granulite terrain. Temperature and pressure constraints have been used to infer a P-T-t path for the exhumation of the basement rocks of Devon Island.