Pure and applied problems in metamorphic geology

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Over half of Canada's land surface is underlain by metamorphic and igneous rocks, and by far the majority of Canada's mineral deposits occur in these areas. Understanding how metamorphic and igneous rocks form is thus of scientific and societal interest. My research program is concerned with the metamorphic half of the relationship, namely metamorphic petrology (= the scientific study of the make-up and genesis of metamorphic rocks). Metamorphic petrology is the primary probe of the burial, heating and exhumation of Earth's crust arising from plate tectonic interactions. When combined with structural, geochronological and thermochronological techniques, metamorphic petrology helps unravel the evolution of Earth's plate tectonic interactions through time, and informs the formation and modification of mineral deposits. Researchers in other fields of geoscience (structure, tectonics, ore deposits) rely on the estimates of pressure (depth) and temperature (P and T) that metamorphic petrologists provide from reading the metamorphic rock record. If inaccurate estimates are provided, it sets back advances in all these areas. The long-term objectives of my research program are thus two-fold: (1) to advance our understanding of metamorphic recrystallization, the aim being to enhance the reliability of our estimates of pressure (depth) and temperature of metamorphosed rocks; and (2) to apply this enhanced understanding in concert with allied techniques to provide insights into the evolution of Earth's orogenic (mountain) belts, especially the southern Canadian Cordillera. Each objective stimulates progress in the other. Proposed short-term objectives include: (1-1)Creating a database of natural mineral assemblages and mineral compositions from metamorphic settings of varying P and T from around the world, and using these to test and refine our thermodynamic modelling of these relationships; (1-2)Creating the first comprehensive mineral assemblage map of Barrow's Zones in Scotland, arguably the most famous and most studied metamorphic sequence on Earth; (1-3)Assessing how reliable are the depths of metamorphism that are inferred from phase equilibrium analysis of metamorphic rocks; (1-4)Analyzing the degree to which rock deformation catalyzes metamorphic recrystallization; and (2-1)Determining the evolution of the Valhalla complex, Shuswap domain, British Columbia, a "type example" of a core complex ( = an "uplift" of mid-deep crustal rocks bounded by faults, such found in extensional oceanic and continental settings around the world). From a training perspective, engagement in this research will educate the next generation of geoscientists, providing them with observational, analytical, computational, interpretational and communication skills that are highly valued in academia, government and industry. They will be in the vanguard of the future generation of adaptable, interdisciplinary geoscientists Canada needs.