Unfolding primary composition of kimberlite melt and processes of mantle enrichment in critical metals; their effect on economic value of kimberlites

揭示金伯利岩熔体的主要成分和关键金属的地幔富集过程；

• 批准号: 572209-2022
• 负责人: Fedortchouk, YanaY
• 金额: $ 1.82万
• 依托单位: Dalhousie University
• 依托单位国家: 加拿大
• 项目类别: Alliance Grants
• 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=750928
• 关键词: Unfolding; primary; composition; kimberlite; melt

Kimberlites, the deepest mantle magmas that reach the surface of the Earth, are the hosts to the major economic diamond deposits. Kimberlites originate deep (> 150 km) in subcontinental mantle due to poorly understood processes of chemical enrichment of the mantle with rare and volatile elements including some of the critical metals. This makes understanding of processes of kimberlite melt production in the mantle very important. The proposed project aims to establish the composition, origin and evolution of primary kimberlite melt and its effect on the eruption mechanism and kimberlite geology. The existing views on the composition of primary kimberlite melt vary between carbonatitic and silicate melt based on (i) study of bulk rock geochemistry and mineralogy of kimberlites and on (ii) experimental melting of possible mantle sources of kimberlites. The proposed project will integrate these studies with a novel method which examines the reaction between kimberlite magma and mantle minerals carried by kimberlites (diamond, chromite, ilmenite, garnet). In response to the crystallization conditions and composition of kimberlite magma, these minerals develop: (i) dissolution features, (ii) compositional zoning, and (iii) rims of secondary mineral phases. The proposed study will use high-pressure-experiments to examine these reactions and apply the results to natural diamonds and Fe-Ti oxides from worldwide kimberlite localities. Collaboration with diamond mining industry provides an exceptional access to the samples with geological control from specific depths and units within composite kimberlite pipes. Knowledge of the composition and evolution of kimberlite melt is essential for understanding: mantle processes leading to kimberlite magmatism, causes of the large variation in kimberlite geology, and their effect on diamond economic potential. The study aims to develop new analytical methods to help improving exploration techniques and assessment of kimberlite bodies, for sustaining and adding value to the existing mines. The proposed research will help to unravel deep mantle processes and improve exploration techniques to benefit diamond mining industry in Canada, the third world largest diamond producer.

金伯利特人是到达地球表面的最深地幔岩浆，是主要经济钻石沉积物的宿主。金伯利特人在次大陆地幔中起源于深（> 150 km），这是由于知识较少的化学富集过程，具有稀有和挥发性元素，包括一些关键金属。这使得对金伯利岩熔体生产的过程非常重要。拟议的项目旨在建立原发金伯利特熔体的组成，起源和进化及其对喷发机制和金伯利特地质的影响。基于（i）基于（i）研究金伯利岩的散装岩石地球化学和矿物质学以及（ii）（ii）基林伯利特（Kimberlite）可能地幔来源的（ii）实验性融化，对原发性金伯利岩组成的现有观点在碳酸盐和硅酸盐融化之间变化。拟议的项目将将这些研究与一种新方法相结合，该方法研究金伯利岩（Kimberlite）（钻石，铬铁矿，伊利米特，石榴石）携带的金伯利特岩浆和地幔矿物之间的反应。为了响应金伯利岩岩浆的结晶条件和组成，这些矿物会发展出来：（i）溶解特征，（ii）组成分区和（iii）继发矿物相的边缘。拟议的研究将使用高压示例来检查这些反应，并将结果应用于全球金伯利特地区的天然钻石和Fe-Ti氧化物。与钻石矿业行业的合作提供了从复合金伯利岩管中特定深度和单位的地质控制样品的特殊访问权限。了解金伯利岩融化的组成和演变对于理解至关重要：地幔过程导致金伯利岩岩浆，金伯利特地质差异很大的原因及其对钻石经济潜力的影响。该研究旨在开发新的分析方法，以帮助改善金伯利岩体的勘探技术和评估，以维持和增加现有矿山的价值。拟议的研究将有助于揭开深层地幔过程，并改善勘探技术，使加拿大第三世界最大的钻石生产商加拿大钻石矿业行业受益。