Quantifying the Pressure, Temperature, and Timing of Metamorphism in the Montresor Belt, Nunavut, Canada

• Main Author: Dziawa, Carolyn
• Format: Thesis
• Language: unknown
• Published: 2016
• Subjects: Nunavut; Canada; Rae
• Online Access: https://curve.carleton.ca/b378da73-ae9e-462c-ad27-67b90e62b471; http://catalogue.library.carleton.ca/record=b3942737; https://doi.org/10.22215/etd/2016-11560

P-T-t conditions are determined for the Montresor belt (Rae Province, Nunavut) using modern thermodynamic modeling and in-situ U-Th-Pb monazite geochronology. Phase equilibrium modeling yields peak P-T estimates of 355 - 455°C and <4200 bar for the upper Montresor belt and 500 - 580°C and <4000 bar for the lower Montresor belt, with a high geothermal gradient of ca. 57°C/km during metamorphism. Forward modeling of garnet crystallization suggests growth along a clockwise, nearly isobaric P-T path from ca. 539 – 544°C and 3090 – 3140 bar. Chemical age dating of metamorphic monazite indicates peak P-T conditions occurred at ca. 1837 ± 8.6 Ma. Altered monazite domains suggest a fluid-mediated alteration event during cooling at ca. 1792 ± 10.1 Ma, associated with the emplacement of dykes into the lower Montresor group. These fluids increased the bulk rock K and caused modification to garnet growth zoning and mechanical fracturing of garnet.