Tracing Early Earth Evolution

这项研究计划建议使用贵金属及其放射性同位素来解决固体地球地球化学中一些最长期和最有争议的问题。地核的形成应该会给地球其他部分的化学物质留下不可逆转的印记。然而，如果核心形成是地幔演化的唯一控制因素，那么许多贵金属，如铂族元素(Pge)，在地幔中仍然是“过度丰富的”。这表明该地幔在形成后不久的某个时间点重新富集化。一项新的研究揭示了在地核形成后近20亿年达到顶峰的PGE的时间上的富集度。我计划利用加拿大北极古老的“绿岩带”中的岩浆岩，对这种重新浓缩的时间和性质进行详细的调查。了解地幔的早期演化对于我们了解地球从最初的吸积到今天是如何在化学和物理上演化的具有重要意义。一些火山岩独特的新鲜性质使我们能够研究地球历史这一关键时期的地球化学变化，**许多重要的贵金属矿床形成于太古宙(3.8和2.5Ga)地球历史的早期阶段，因此了解地幔中PGE的丰度如何随时间变化对太古宙贵金属矿床的起源具有重要影响。此外，绿岩带是加拿大和全球主要贱金属、金矿和PGE矿床的所在地，因此了解它们的成因和喷发时间对于矿产勘探至关重要。该研究计划将提供在几个高科技行业中应用的最先进的地球化学技术方面的培训，并将培训HQP北极地质和野外技术。这项研究建立在我在英国建立的国际声誉基础上，我在铂族元素和Os同位素研究方面的领先地位适用于各种地质和生化/药理学问题。为这一研究计划建立的技术在加拿大尚不存在，因此将提高加拿大作为固体地球地球化学领域领导者的声誉。

This research program proposes to use precious metals and their radiogenic isotopes to address some of the most long-standing and controversial issues in solid Earth geochemistry. The formation of the Earth's core should have left an irreversible imprint on the chemistry of the rest of the Earth. Yet many precious metals, such as the platinum group elements (PGEs), remain "over-abundant" in the mantle if core-formation was the sole control on its evolution. This indicates that the mantle was re-enriched at some point soon after its formation. New research has revealed hints of a temporal enrichment in PGEs that peaked almost 2 billion years after core formation. I plan a detailed investigation into the timing and nature of this re-enrichment, using magmatic rocks in Arctic Canada's ancient "greenstone belts". Understanding the early evolution of the Earth's mantle has fundamental implications for our knowledge of how the Earth evolved chemically and physically, from its initial accretion, to today. The uniquely fresh nature of some of the volcanic rocks allow investigation of geochemical changes in this critical period of Earth history, ** Many important precious metal deposits were generated in the earliest phases of Earth history, within the Archean eon (3.8 and 2.5 Ga) and so understanding how PGE abundances may have changed with time in the mantle has an important bearing on the origin of Archean precious metal deposits. Moreover, greenstone belts are host to major base-metal, gold and PGE deposits in Canada and globally, hence understanding their genesis and time of eruption is crucial for mineral exploration. The research program will provide training in state-of-the-art geochemical techniques that have applications in several high-tech industries and will train HQP in Arctic geology and field techniques . The research builds on my international reputation, established in the UK, for leadership in platinum group element and Os isotope research applied to diverse geological and biochemical/pharmacological problems. The techniques to be established for this research program do not yet exist in Canada and so will enhance Canada's reputation as a leader in the field of solid-Earth geochemistry.