The influence of lithospheric structure and composition on the distribution of CO2-rich intraplate volcanism and REE mineralisation

岩石圈结构和成分对富CO2板内火山作用和稀土矿化分布的影响

• 批准号: NE/Y000218/1
• 负责人: Sally Gibson
• 金额: $ 106.53万
• 依托单位: University of Cambridge
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2024
• 资助国家: 英国
• 起止时间: 2024 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FY000218%2F1
• 关键词: influence; lithospheric; structure; composition; distribution

Most of the Earth's volcanism occurs at the diverging and converging boundaries of tectonic plates. While igneous activity is less common in intraplate continental settings, these magmas hold essential clues on the evolution of Earth's outer rigid shell (lithosphere) and the generation and distribution of commercially significant natural resources, including rare earth elements (REE) and critical metals (e.g. Nb & Ti), essential for renewable energy and other infrastructure.The type of continental intraplate magmatism is governed by the lithospheric thickness and composition and temperature in the lithosphere and underlying mantle. Intraplate basalts are produced by partial melting in the asthenosphere beneath thin (<60-70 km) lithosphere, whereas carbonatites and associated alkaline igneous rocks, which host most of the world's REE deposits, are emplaced through thicker (~70-120 km) lithosphere. This contrasts with diamondiferous kimberlites and lamproites that occur in Precambrian cratons, with lithosphere over 150 km thick.Carbonatite complexes are found in continental rift zones, Large Igneous Provinces and syn- to post-collisional zones. Previous studies of their origins have largely focused on their relationship with surface geology but here we innovate by examining their distribution with deep lithospheric structure. Our work is timely because:1. It follows the rapid recent growth in the number of seismic stations around the world, which now permits seismic tomography to map lateral variations in lithospheric structure at higher resolution beneath most continental areas than previously possible. High-resolution geophysical models of lithospheric structure together with access to samples collected from global carbonatite complexes of different ages enables novel, unique insights into their distribution in space and time.2. Keeping up with increasing demand to supply REEs, essential for products in emerging clean, green technologies, electronic devices and petroleum-refining catalysts, presents a serious global challenge. Over 95% of the world's usable REEs are produced from the Bayan Obo mine (China), raising concerns over the security of supply for Europe (e.g. EURARE project http://www.eurare.eu/about.html) and highlighting the need to identify sources of potential future deposits. This exploration is essential for long-term planning and growth, but Europe currently has no mines supplying REEs, although there are a number of areas with geology often associated with REE mineralisation, including alkaline igneous rocks found in south-west Greenland, Finland and Scandinavia.The main goal of our research is to quantify the relationship between lithospheric thickness and the global distribution of carbonatite complexes with their associated REE, Ti, Nb and Ta deposits, and assess how this has varied during Earth's evolution. This relates to large-scale, complex interactions within the Earth system. We have conducted pilot studies at global and regional scales, focused on E Africa and western S America, which revealed: (i) a correlation between the distribution of continental magma type and lithospheric thickness; (ii) a strong relationship between carbonatite complexes and the margins of ancient cratons; (iii) Phanerozoic carbonatite magmatism is often located on thinner lithosphere than its Precambrian counterpart. We seek to build on the pilot study by improving the resolution of the geophysical data, expanding the analysis to all the continents, and compiling comprehensive geochemical datasets for carbonatite complexes and associated alkaline igneous rocks of different ages together with their REE deposits. Using in-depth statistical analysis of the geophysical and geochemical data, we will quantify the correlations, establish how they varied over geological time, build a probabilistic predictive model for the location of the rocks and deposits, and advance our knowledge of lithospheric evolution

地球的大部分火山主义发生在构造板的分歧和融合边界上。虽然火成活性在插入式大陆环境中较不常见，但这些岩浆对地球外壳（岩石圈）的演变以及商业上重要的自然资源的产生和分布（包括稀土元素（REE）（REE）和关键金属（例如NB＆TI）（例如，NB＆TI）的产生和分布构成了基础构造的必不可少的，是可重新设计的型号和其他基础仪式。以及岩石圈和下层地幔中的成分和温度。底层玄武岩是通过在薄（<60-70 km）岩石圈下的小动育圈中部分熔化产生的，而碳酸盐岩和相关的碱性火成岩（载有世界上大部分REE沉积物），它是通过厚（70-120 km）岩石圈的。这与前寒武纪的钻石金伯利石和灯泡形成鲜明对比，岩石圈厚度超过150 km。在大陆裂谷区，大火成岩省，综合到后倾斜后区域中发现了碳酸盐岩络合物。先前对其起源的研究主要集中在它们与表面地质学的关系上，但是在这里我们通过深层岩石圈结构检查它们的分布来创新。我们的工作及时是因为：1。它遵循世界各地的地震站数量的近期增长，现在允许地震层析成像绘制在大陆区域以下岩石圈结构的横向变化，而不是以前的大陆区域。岩石圈结构的高分辨率地球物理模型，以及从不同年龄的全球碳酸盐岩复合物收集的样品的访问，可以使新颖的独特见解对它们在时空中的分布进行独特的见解。2。跟上供应REE的需求不断增长，这对于新兴的清洁，绿色技术，电子设备和石油催化剂的产品中至关重要，带来了严重的全球挑战。世界上有95％以上的可用REE是由Bayan Obo矿山（中国）生产的，这引起了人们对欧洲供应安全性的担忧（例如Euroare Project http://www.eurare.eu/about.html），并突出了确定潜在未来存款来源的需求。 This exploration is essential for long-term planning and growth, but Europe currently has no mines supplying REEs, although there are a number of areas with geology often associated with REE mineralisation, including alkaline igneous rocks found in south-west Greenland, Finland and Scandinavia.The main goal of our research is to quantify the relationship between lithospheric thickness and the global distribution of carbonatite complexes with their associated REE, Ti, Nb and Ta deposits, and assess在地球进化过程中，情况有何不同。这与地球系统内的大规模，复杂的相互作用有关。我们在全球和区域量表上进行了试点研究，该研究的重点是非洲和西方的美国，该研究揭示了：（i）大陆岩浆类型的分布与岩石圈厚度之间的相关性； （ii）碳酸盐岩络合物与古代克拉通的边缘之间的密切关系； （iii）磷酸化碳酸盐岩岩浆通常比其前寒武纪对应物的岩石圈位于较薄的岩石圈上。我们试图通过改善地球物理数据的分辨率，将分析扩展到所有大陆，并为碳酸盐岩配合物以及相关的不同年龄量的相关碱性岩石及其REE沉积物汇编全面的地球化学数据集，并汇编全面的地球化学数据集，并汇编全面的地球化学数据集，并汇编全面的地球化学数据集，并汇编全面的地球化学数据，以及其REE沉积。使用对地球物理和地球化学数据的深入统计分析，我们将量化相关性，确定它们在地质时代的变化，为岩石和沉积物的位置建立概率预测模型，并促进我们对岩石圈进化的了解