Precambrian Earth Evolution

该计划将研究地壳/地幔系统的起源和演化，从地球形成的46亿年前到现在。地球自形成以来一直在缓慢冷却，这在整个历史上推动了地球进化的深刻变化。一些基本的问题仍然存在，比如第一个海洋是什么时候形成的，生命是什么时候出现的，第一个大陆是如何形成的，现代的板块构造是什么时候开始的，以及全球岩浆活动的灾难性事件在热损失机制、超级大陆的裂谷、大灭绝和极端气候中扮演了什么角色。

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.