Carbonatites in plate-collision zones: implications for mantle processes, carbon cycling and rare-earth metallogeny

板块碰撞区的碳酸岩：对地幔过程、碳循环和稀土成矿的影响

• 批准号: RGPIN-2018-05051
• 负责人: Chakhmouradian, Anton
• 金额: $ 4.37万
• 依托单位: University of Manitoba
• 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=754966
• 关键词: Carbonatites; plate; collision; zones; implications

Carbonatites are a remarkable manifestation of low-volume, mantle-derived magmatism in terms of their composition, physical properties and industrial potential. These rocks and their weathering products have long served as the principal source of such technologically “critical” metals as rare-earth elements (REE) and niobium. Despite the large volume of literature published on this subject, no consensus has been reached yet on such key issues as the role of crust recycling and magma-crust interaction in carbonatite petrogenesis, the nature of processes responsible for the concentration and dispersal of rare metals in carbonatites subjected to fluid infiltration, deformation and metasomatism, and the applicability of specific geochemical characteristics (e.g., element or isotope ratios) to exploration vectoring. In recent years, revision of the previously existing models of carbonatite evolution has been necessitated due to: an increasing number of carbonatite discoveries in (paleo)orogenic belts, the realization that some of the most important REE deposits are associated with plate-collision processes, and new isotopic evidence. The proposed research program is aimed at acquiring new data to address the existing knowledge gaps and to provide a basis for the development of a petrogenetic-metallogenic model for carbonatitic magmatism in plate-collision zones. The novelty of the proposed work is in its integrated and inclusive approach, and its focus on rocks and mineral deposits for which little isotope data are presently available. The program builds on my 25 years of research experience with carbonatites and ongoing collaboration with the Manitoba Geological Survey. The principal expected outcomes of the next Discovery Grant cycle are an improved understanding of the mantle source(s) of carbonatites in plate-collision zones, of geodynamic and structural controls on carbonatitic magmatism in these settings, and of the relative contribution of source-specific, magmatic and postemplacement processes to the development of rare-metal deposits. Progress in these areas will provide a basis for refining the current mineral exploration practices. Other benefits of the proposed program will be in the publication of new geological data for a number of potential exploration targets, and in the training of highly-qualified personnel equipped with theoretical knowledge and practical skills required for mineral exploration and research. The University of Manitoba has unique instrumental capabilities for providing this type of training. My previous work on carbonatites has been recognized in, and supported by, academic, industrial and government sectors. The results of the proposed research will be disseminated through publications, presentations at conferences and mining conventions, workshops for knowledge users and other forms of outreach.

碳酸盐岩在成分、物理性质和工业潜力方面是低体积地幔岩浆作用的显著表现。长期以来，这些岩石及其风化产物一直是稀土元素(REE)和Nb等技术“关键”金属的主要来源。尽管发表了大量关于这一主题的文献，但在以下关键问题上尚未达成共识：地壳再循环和岩浆-地壳相互作用在碳酸盐岩成因中的作用；导致稀有金属在碳酸盐岩中因流体渗透、变形和交代而聚集和扩散的过程的性质；以及特定的地球化学特征(如元素或同位素比率)对勘探指导的适用性。近年来，由于在(古)造山带中发现了越来越多的碳酸盐岩，认识到一些最重要的稀土矿床与板块碰撞过程有关，以及新的同位素证据，有必要对以前存在的碳酸盐岩演化模式进行修订。拟议的研究方案旨在获得新的数据，以填补现有的知识空白，并为建立板块碰撞带碳酸盐岩岩浆作用的成岩成矿模式提供基础。拟议工作的新颖性在于其综合和包容的方法，其重点是目前几乎没有同位素数据的岩石和矿藏。该项目建立在我25年的碳酸盐研究经验和与马尼托巴省地质调查局的持续合作的基础上。下一个发现赠款周期的主要预期成果是更好地了解板块碰撞带中碳酸盐岩的地幔来源(S)、地球动力学和构造对这些背景下碳酸盐岩岩浆活动的控制，以及特定来源、岩浆和侵位后过程对稀有金属矿床开发的相对贡献。这些领域的进展将为完善目前的矿产勘探实践提供基础。拟议计划的其他好处将是公布一些潜在勘探目标的新地质数据，以及培训具备矿产勘探和研究所需的理论知识和实践技能的高素质人员。马尼托巴大学在提供这类培训方面拥有独特的工具能力。我之前在碳酸盐岩方面的工作得到了学术界、工业界和政府部门的认可和支持。拟议研究的结果将通过出版物、在会议和采矿大会上的陈述、知识用户讲习班和其他形式的外联活动来传播。