Applied thermochronology and the isotopic record of low-temperature crustal-scale tectonic processes

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Mountain belts form in many ways but the two most common end-members are through squeezing the Earth's crust (compression) and stretching it (extension). A particular focus of this Discovery research program is aimed at the cores of mountain belts where most of the transport of crustal heat and mass occurs. Resolving a rock's thermal evolution in these settings has direct influence on the advancement of geodynamic, climate, and landscape evolution models. The processes that form rocks at high temperatures in mountain belts are reasonably well characterized. Little is known, however, of the timescales that rocks take to emerge at the Earth's surface, nor the effects of the deformation pathway on the isotopic systems. To better understand these processes, a quantitative understanding of the thermal evolution of rocks as they move through the Earth's outer shell and under a range of geologic settings is required. This research proposal addresses these needs by advancing innovative scientific approaches that shed light on rock's change in temperature, depth and deformation-state through time during mountain growth and decay. The rock's "travel log" is gleaned from detailed chemical and structural characterization of mineral assemblages and textures. Collectively, these make up the fingerprint of the tectonic process at work in mountains and advance our knowledge of how long-term, crustal-scale processes link to the dynamics of climate, surface processes and the Earth's solid interior. Together with Discovery Grant support, my work embarks upon a new phase of Earth science research involving students and collaborators, developing innovative geochronology techniques, and rewarding my students with having access to, and training on, world-class instruments. Although concentrating on fundamental issues such as the life cycle of mountain belts, this research has impacts through the Earth Sciences, from submicron-scale isotope mobility to mega-scale tectonism. More directly, this research has specific applications to natural resource exploration within Canada, including determining the timing and duration of ore-bearing fluid flow and the burial history of petroleum reservoirs.