Precambrian Earth Evolution

前寒武纪地球演化

• 批准号: RGPIN-2018-04940
• 负责人: Heaman, Larry
• 金额: $ 8.89万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=750899
• 关键词: Precambrian; Earth; Evolution

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.

拟议的研究计划将调查地壳/地幔系统的起源和演变，从地球形成时~ 46亿年前到今天。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演变的深刻变化。基本问题仍然存在，例如第一个海洋何时形成，生命何时出现，第一个大陆如何形成，现代式板块构造开始，以及全球镁铁质岩浆活动的灾难性事件对热损失机制的作用，超级大陆的裂谷，进行的基础科研涉及一种包括实地考察的综合方法（地质测绘和样品采集）、岩相学、地球化学、地质年代学（年龄测定）和原位示踪同位素技术。计划中的研究将利用并在某些情况下开发新的最先进和尖端的质谱技术来确定高精度的U-Pb辅助矿物（斜锆石，单斜辉石，钙钛矿，锆石，常规热电离质谱和原位高空间分辨率测定镁铁质和超镁铁质岩石年龄（<20微米）的方法，同时使用激光烧蚀多收集器电感耦合等离子体质谱和二次离子质谱。计划的研究将解决时间，性质，前寒武纪镁铁质和超镁铁质岩浆活动的成因及其在古超大陆裂谷、大陆岩石圈建造、古洋壳俯冲和原生矿床形成中的作用（如，钻石、贱金属和铂族元素）。这项研究的主要成果是更好地了解前寒武纪构造板块的配置，更好地了解未发现的加拿大矿产资源的起源，位置和环境，这对加拿大经济的可持续发展和加拿大钻石业的未来生存能力至关重要。本提案中概述的研究将开发新的技术和方法，以便能够测量地质年代和地球最小颗粒的示踪同位素信息，对科学研究界和寻找矿产资源的勘探公司具有重大价值。