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

点击翻译按钮获取中文摘要

Broad tectonic stresses over the Earth’s outer solid shell cause localized deformation along fault zones. Deformation leads to the displacement of rock, and this large-scale movement of heat and fluids during mountain building exerts a major control on the burial, heating, and potential melting of rock, and plays a key role in the distribution of economic ore deposits and hydrocarbon reservoirs. Understanding the tempo of these tectonic events across deep time is fundamental for making predictions about the solid Earth on shorter timescales. The processes that deform rocks at high temperatures deep in the Earth are reasonably well characterized. Little is known, however, of the timing and rate that rocks take to emerge at Earth's surface, nor the effects of the deformation pathway on the isotopic systems used to understand this phenomena. To better decipher these temporal riddles, a quantitative understanding of the thermal history of rocks as they move through the Earth’s crust 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 tectonic displacements. 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 the crust and advance our knowledge of how long-term, crustal-scale processes link to the dynamics of climate, surface processes and 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, including determining the timing and duration of ore-bearing fluid flow and the burial history of petroleum reservoirs.