Magmatism, sedimentation and the uranium mineral system in the Paleoproterozoic core of Canada

加拿大古元古代核心的岩浆作用、沉积作用和铀矿物系统

• 批准号: RGPIN-2017-04427
• 负责人: Ansdell, Kevin
• 金额: $ 2.84万
• 依托单位: University of Saskatchewan
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=711035
• 关键词: Magmatism; sedimentation; uranium; mineral; system

The Precambrian Shield makes up a significant portion of the crust in Canada, and many of the Archean (>2.5 billion years old) components were joined together about 1.8 billion years ago during a cataclysmic collision, called the Trans-Hudson orogeny, that is preserved in a linear belt that extends from Saskatchewan to Baffin Island. The collision, which was related to the motion of lithospheric plates, formed a mountain range that was probably of the same scale as the present-day Himalayas. In the lead up to the collision, there were complex interactions between different crustal elements which generated magmas, sediments, and structures. The aim of part of this research, which involves mapping and sampling in the field by a number of graduate and undergraduate students, and the application of modern analytical techniques for the analysis of trace elements and isotopes is to unravel the interaction between different crustal blocks just prior to the major collision 1.8 billion years ago, with a focus on the well-exposed rocks in northern Saskatchewan and Manitoba. It will be necessary to define the composition of different parts of the crust and mantle in order to understand how they interacted. In addition the Precambrian rocks in central Canada host world-class hydrothermal deposits of copper, zinc, gold, uranium, and rare earth elements, and their formation is intimately related to the evolution of the mountain belt. The research will focus on the youngest igneous rocks (about 1.85 to 1.82 billion years old) that formed during this mountain-building event, partly because this represents the most complex part of this event, and will provide a chemical and isotopic “fingerprint” of the parts of the crust and mantle that might have been involved in the formation of these rocks. In addition, the sedimentary rocks that formed in basins as continental collisions were occurring preserve zircons as detrital minerals, and they record the age and character of the source regions for these sediments. The mountain belt was then eroded, and sediments were deposited in the uranium-rich Athabasca Basin, under which is a zone of alteration that may represent an ancient weathered profile. This will be examined to determine its origin, and whether this might be an important source of metals, including uranium, for the younger mineral deposits. Direct outcomes of all this work will be student theses and journal papers, and well-trained new geoscientists to work in academia, government or the Canadian minerals industry.

前寒武纪地盾构成了加拿大地壳的重要组成部分，许多太古宙（> 25 亿年）的组成部分在大约 18 亿年前的一次灾难性碰撞中连接在一起，称为跨哈德逊造山运动，该运动被保留下来在从萨斯喀彻温省延伸到巴芬岛的线性带中，与岩石圈板块运动有关的碰撞形成了一条可能与今天规模相同的山脉。在碰撞之前，不同的地壳元素之间发生了复杂的相互作用，产生了岩浆、沉积物和结构。这项研究的一部分目的是由许多研究生和本科生在现场进行测绘和采样。学生们应用现代分析技术进行微量元素和同位素分析，旨在揭示18亿年前大碰撞之前不同地壳块体之间的相互作用，重点关注北部地区暴露良好的岩石。萨斯喀彻温省和马尼托巴省有必要定义地壳和地幔不同部分的成分，以便了解它们如何相互作用。此外，加拿大中部的前寒武纪岩石蕴藏着世界级的铜、锌、金、铀热液矿床。 、稀土元素，其形成与山地带的演化密切相关。 该研究将重点关注在这次造山事件中形成的最年轻的火成岩（约 1.85 至 18.2 亿年），部分原因是这代表了该事件中最复杂的部分，并将提供化学和同位素“指纹”可能参与这些岩石形成的地壳和地幔部分此外，在大陆碰撞时发生的盆地中形成的沉积岩保留了作为碎屑矿物的锆石，以及他们记录了这些沉积物来源的年龄和特征，然后山脉被侵蚀，沉积物沉积在富含铀的阿萨巴斯卡盆地，该盆地下面是一个可能代表古代风化剖面的蚀变带。检查以确定其来源，以及这是否可能是较年轻矿藏的金属（包括铀）的重要来源，所有这些工作的直接成果将是学生论文和期刊论文，以及训练有素的新矿床。在学术界、政府或加拿大矿产行业工作的地球科学家。