Precambrian Earth Evolution

前寒武纪地球演化

• 批准号: RGPIN-2018-04940
• 负责人: Heaman, Larry
• 金额: $ 4.44万
• 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: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=691063
• 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.***

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。*******将进行的基础科学研究包括一种综合方法，包括实地考察（地质制图和样品收集）、岩石学、地球化学、地质年代学（年龄测定）和现场示踪同位素技术。计划中的研究将利用，并在某些情况下，开发新的最先进和最尖端的质谱技术，以确定高精度的U-Pb辅助矿物(坏辉石、斜辉石、钙钛矿、锆石、利用传统的热电离质谱法和原位高空间分辨率（<20微米）的激光烧蚀多收集器电感耦合等离子体质谱法和二次离子体质谱法测定了基性岩和超基性岩的锆石年代。*******计划中的研究将探讨前寒武纪基性和超基性岩浆活动的时间、性质和成因，以及它在古代超大陆的裂谷、大陆岩石圈的形成、古代海洋地壳的俯冲和原生矿床（如钻石、贱金属和铂族元素）的产生中的作用。这项研究的主要成果是更好地了解前寒武纪构造板块构型，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行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，允许测量地球最小颗粒的地质时间和示踪同位素信息，这将对科学研究界和寻找矿产资源的勘探公司具有重要价值