Tracing battery metal (Li) mobility in pegmatite systems

全球经济的脱碳是一个紧迫的挑战，地球科学将在其中发挥关键作用。向可再生能源发电和储能的过渡将需要在未来几十年内大幅增加关键金属的采购，特别是锂离子电池的关键组成部分锂（Li）。锂的来源将显著增加，因此，更好地了解和寻找迄今为止研究较少的含锂矿床将成为一个新的和迫切的焦点。这些矿床是通过提取高度演化的岩浆，或通过富锂和富硅源的部分熔融（例如，变质沉积物）。尽管如此，伟晶岩演化的精确机制：（i）熔体形成（ii）金属禀赋（iii）复杂结晶，特别是（iv）控制经济矿化的条件，知之甚少，李的阻碍模式（和Li-Cs-Ta-Sn）存款的形成和开发新的勘探工具。本项目将制定一项动态研究计划，包括（i）至少在一个研究区进行实地观察和取样（津巴布韦），重点是花岗岩单元的侵位历史，利用横切关系和深入花岗岩的断面，建立侵位历史和成矿事件的三维视图;（ii）利用激光烧蚀ICPMS对矿物相进行矿物地球化学研究，以跟踪单个样品中矿物生长所记录的结晶历史;以及（iii）矿物地球化学建模，以限制成矿的物理化学条件。可以采取一系列其他原地和全岩地球化学和同位素方法。分析工作将在圣安德鲁斯大学和英国地质调查局（BGS）进行。圣安德鲁斯地质年代学实验室（StAGE）和同位素地球化学实验室（StAIG）配备了各种基于溶液和激光烧蚀的MC-ICPMS和QQ-ICPMS设施，以进行矿物相的原位微量元素和同位素分析。此外，圣安德鲁斯化学学院还配备了电子探针和SEM，以进行原位分析和电子成像。英国地质调查局的地质年代学和示踪设施提供了广泛的仪器，包括新安装的SELFRAG（高压破碎系统）矿物分离仪器;激光烧蚀MC和SF-ICP-MS仪器，低Pb空白清洁套件，和最先进的Isotopx TIMS，用于高精度（CA）-ID-TIMS U-铅地质年代学：该项目的最终目标是确定所研究地点锂的流动性、来源的作用以及这些金属的普通地壳丰度是否足以产生经济矿床，岩浆演化过程中金属活动性的性质和蒸汽饱和度，以及矿化伟晶岩和无矿伟晶岩之间的不同成因，以建立广泛适用的成因模式。该项目中使用的多学科方法有可能改变我们对这些系统的理解，其结果将引起岩石学家，经济地质学家和勘探公司的广泛兴趣。更好地表征含电池金属的花岗岩-伟晶岩系统将最终有助于其勘探和开采，有助于确保这种金属的新供应，这是社会脱碳的关键。培训将采用以下分析技术和软件：-LA ICP MS-EPMA和SEM-地球化学工作台-SuperPHREEQC和PHREEQC-ThermoCalc

The decarbonisation of the global economy is a pressing challenge in which Geoscience will play a key role. The transition to renewable power generation and storage will require a significant uptick in the sourcing of key metals over the next few decades, in particular lithium (Li), a key component of Li-ion batteries. A significant uptick in the sourcing of Li is predicted, hence a new and urgent focus in better understanding and exploring for Li-bearing deposits, which have hitherto been poorly studied.Geologically, Li are principally found associated with the intrusion of silica-rich pegmatites. This deposits form endogranitic with the extraction of highly evolved magma, or by partial melting of Li- and Silica-rich sources (e.g., metasediments). Nonetheless the precise mechanisms of pegmatite evolution: (i) melt formation (ii) metal endowment, (iii) complex crystallization and specially (iv) the conditions that control economic mineralization, are poorly understood, hindering models of Li (and Li-Cs-Ta-Sn) deposit formation and development of new exploration tools.This project will develop a dynamic research plan involving (i) field observations and sampling in at least one study area (Zimbabwe) with focus on the emplacement history of granite units using cross-cutting relationships and transects deep into the granite to build 3 dimensional views of the emplacement history and ore events; (ii) mineral geochemistry on mineral phases by laser ablation ICPMS to track crystallisation histories recorded by mineral growth within individual samples; and (iii) thermodynamic-geochemical modelling to constrain mineralization physico-chemical conditions. A range of other in-situ and whole-rock geochemical and isotopic approaches may be undertaken. Analytical work will be carried out at the University of St Andrews and the British Geological Survey (BGS). The St Andrews Geochronology Laboratory (StAGE) and Isotope Geochemistry Laboratory (StAIG) are equipped with a variety of solution-based and laser ablation MC-ICPMS and QQQ-ICPMS facilities to undertake in-situ trace element and isotopic analyses of mineral phases. Additionally, the St Andrews School of Chemistry is equipped with an electron microprobe and SEM to perform in-situ analysis and electron-based imaging. The Geochronology and Tracers Facility at the BGS provides a wide range instrumentation available including a newly installed SELFRAG (high-voltage fragmentation system) instrument for mineral separation; laser ablation MC and SF -ICP-MS instruments, a low-Pb blank clean suite, and a state-of-the-art Isotopx TIMS for high- precision (CA)-ID-TIMS U-Pb geochronology.The ultimate goal of the project is to characterize the mobility Li in the studied site(s), the role of source and whether ordinary crustal abundances of these metals are sufficient to generate economic deposits, the nature of metal mobility during magmatic evolution and vapour saturation, and the different petrogenesis between mineralized and barren pegmatites, to build widely applicable genetic models. The multi-disciplinary approach used in this project has the potential to transform our understanding of such systems and the results will be of wide interest to petrologists, economic geologists, and exploration companies. Better characterization of battery metal-bearing granitic-pegamatite systems will ultimately help in their exploration and extraction, helping ensure new supplies of this metal key to the decarbonisation of society.Training will be taken in the following analytical techniques and software:-LA ICP MS-EPMA and SEM-Geochemist Workbench-SuperPHREEQC and PHREEQC-ThermoCalc