Precambrian Earth Evolution

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The proposed research program will investigate the origin and evolution of Earth's crust/mantle system, from when the Earth formed ~4.6 billion years ago to present day. The Earth has been cooling slowly since it formed which has driven profound changes in the evolution of the planet throughout its history. Fundamental questions remain, such as when did the first oceans form, when did life emerge, how did the first continents form, when did modern-style plate tectonics begin, and what is the role of catastrophic episodes of global mafic magmatism on heat-loss mechanisms, rifting of supercontinents, mass extinctions and extreme climate. The basic scientific research to be conducted involves an integrated approach involving fieldwork (geologic mapping and sample collection), petrography, geochemistry, geochronology (age dating), and in situ tracer isotopic techniques. The planned research will utilize and, in some cases, develop new state-of-the-art and cutting-edge mass spectrometry techniques to determine high-precision U-Pb accessory mineral (baddeleyite, clinopyroxene, perovskite, zircon, zirconolite) dates of mafic and ultramafic rocks by conventional thermal ionization mass spectrometry and in situ high spatial resolution (<20 micron) methods using both laser ablation multi-collector inductively coupled plasma mass spectrometry and secondary ion mass spectrometry. The planned research will address the timing, nature, and cause of Precambrian mafic and ultramafic magmatism and its role in the rifting of ancient supercontinents, building continental lithosphere, subduction of ancient oceanic crust, and the generation of primary mineral deposits (e.g., diamonds, base metals and platinum group elements). A primary outcome of this research is a better understanding of Precambrian tectonic plate configurations and better insight into the origin, location and setting of undiscovered Canadian mineral resources, critical for a sustainable Canadian economy and the future viability of the Canadian diamond industry. The research outlined in this proposal will develop new techniques and approaches that allow measurement of geologic time and tracer isotope information on Earth's smallest particles and will be of great value to the scientific research community and to exploration companies searching for mineral resources.