A genetic model and geochemical exploration tools for magnetite-apatite REE deposits

磁铁矿-磷灰石稀土矿床的成因模型和地球化学勘探工具

• 批准号: 537218-2018
• 负责人: WilliamsJones, Anthony
• 金额: $ 2.79万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Collaborative Research and Development Grants
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=720251
• 关键词: genetic; model; geochemical; exploration; tools

The heavy rare earth elements (HREE) and Nd are of strategic importance because of their application in new technologies designed to address the issue of global warming, and are critical raw materials for future economic development. Because there are no major producers of these metals outside China, Focus Graphite Inc. has a significant opportunity to exploit the potential resources of the Kwyjibo magnetite-apatite REE deposits (Québec). The proposed research builds on research undertaken through the NSERC Engage program and aims to formulate a comprehensive model for the genesis of the deposits and develop tools that could be used in their ongoing exploration. In contrast to most base and precious metal ore systems, for which robust genetic models have been developed, we have a poor understanding of how the REE are concentrated to economic levels, and almost no understanding of how this occurs in magnetite-apatite rocks. Indeed, even the genesis of magnetite-apatite rocks is a matter of debate, with opinion being divided over whether they are magmatic or hydrothermal in origin. Moreover, many of them have sub-economic concentrations of the REE. The Kwyjibo deposits are exceptional in having high concentrations of the REE, particularly the HREE. This may be because they experienced subsequent hydrothermal alteration that remobilised the REE and could have introduced additional REE resources. We plan to study the magnetite-apatite rocks and their hydrothermally altered equivalents using the results of a combination of major and trace element analyses of the bulk rocks, minerals and, if present, melt and fluid inclusions. These data will be complemented by results of analyses of the stable and radiogenic isotope chemistry of mineral separates and bulk rocks. In addition, we will conduct microthermometric analyses of fluid inclusions and thermodynamic modelling. The sum of these activities will allow us to determine the genesis of the magnetite-apatite rocks, the source of the REE, and how hydrothermal fluids mobilised the REE. Through an analysis of the mineral chemistry, the project should also yield tools for the exploration and discovery of similar deposits both locally and elsewhere in Canada.

重稀土元素（HREE）和Nd因其在旨在解决全球变暖问题的新技术中的应用而具有战略重要性，并且是未来经济发展的关键原材料。由于中国以外没有这些金属的主要生产商，Focus Graphite Inc. 有很大机会开发 Kwyjibo 磁铁矿-磷灰石稀土矿床（魁北克）的潜在资源。拟议的研究建立在通过 NSERC Engage 计划进行的研究的基础上，旨在制定矿床成因的综合模型，并开发可用于正在进行的勘探的工具。与大多数基础金属和贵金属矿石系统相比，我们对稀土元素如何集中到经济水平知之甚少，并且几乎不了解这种现象在磁铁矿-磷灰石岩石中是如何发生的。事实上，即使是磁铁矿-磷灰石岩石的成因也是一个有争议的问题，人们对于它们是岩浆还是热液的起源存在分歧。此外，其中许多国家的稀土元素集中程度低于经济水平。 Kwyjibo 矿床的稀土元素浓度特别高，特别是重稀土元素。这可能是因为它们经历了随后的热液蚀变，重新激活了稀土元素，并可能引入了额外的稀土元素资源。我们计划利用对大块岩石、矿物以及熔体和流体包裹体（如果存在）的主量元素和微量元素分析的结果，研究磁铁矿-磷灰石岩石及其热液蚀变等同物。这些数据将得到矿物分离物和块状岩石的稳定和放射性同位素化学分析结果的补充。此外，我们还将对流体包裹体进行显微测温分析和热力学建模。这些活动的总和将使我们能够确定磁铁矿-磷灰石岩石的成因、稀土元素的来源以及热液如何动员稀土元素。通过对矿物化学的分析，该项目还应该为加拿大当地和其他地方勘探和发现类似矿床提供工具。