Towards a process-based understanding of rare-earth element deposits

这项研究涉及一组名为稀土元素(REES)的17种元素，这些元素构成了现代社会所依赖的高科技设备的重要组成部分。也许最重要的是，稀土元素是风力涡轮机、电池和光伏电池等新兴绿色技术不可或缺的一部分，这些技术将对应对气候危机至关重要，因为能源部门是人类温室气体排放的最大单一贡献者。我们对电子产品的依赖和可再生能源的发展正在推动稀土需求的快速增长。然而，全球稀土产量仅限于相对较少的稀土矿床，其中90%产于中国。因此，人们对应对日益增长的稀土需求的能力和获得这些重要资源的安全感到严重关切。因此，寻找新的和多样化的稀土来源对于维持我们的生活方式和促进我们向低碳未来的过渡至关重要。稀土最重要的来源是‘碳酸盐岩’和‘碱性’火成岩。这些岩石在地球深处形成岩浆，然后上升并在较浅的深度固化，浓缩最终暴露在地球表面的稀土。然而，导致它们在稀土中富集的确切形成过程却知之甚少，而且它们在地表的小尺寸使得它们极难被发现。这个项目将增加我们对这些岩石的了解，并开发一种新的工具，使用三步法有效地定位与这些岩石类型相关的未来稀土矿床。我的研究项目的第一步将开发一个计算工具来模拟碳酸岩和碱性火成岩的形成。这一工具可以提高我们对这些含稀土火成岩在地球上的分布的了解和预测。我的研究的第二步将通过分析它们的形成在周围地质中留下的特征‘模式’，为寻找稀土矿床奠定基础。当碳酸盐岩和碱性岩石在较浅的深度固化时，它们改变了周围的“乡村岩石”，形成了被称为“辉岩”的蚀变带。这些辉长岩具有复杂的结构和结构，人们对其了解不多。通过对辉长岩的深入了解，我们可以利用它们作为难以捉摸的稀土矿床的“路标”，因为辉长岩带比产生它们的含稀土的火成岩更大，也更容易找到。为了实现这一点，我将对两个著名的闪锌矿带进行详细的研究，它们展示了不同的结构和纹理。通过将结构和化学观察与我的计算模型相结合，我将建立对它们的形成和REE富集性的整体理解。这种对含稀土的火成岩侵位和辉长岩形成的新认识将使我的项目的最后阶段成为可能：开发利用遥感(航空)技术寻找稀土矿床的新方法。我将与行业合作伙伴一起开发这些技术，它们将搜索辉石带，作为与之相关的稀土矿床的路标。这一方法很可能特别有利于在迄今勘探程度较低的新兴前沿地区，如北极和东非寻找稀土矿藏。

This research relates to a set of 17 elements called the rare-earth elements (REEs), which form an essential component of the high-tech devices on which modern society depends. Perhaps most importantly, REEs are integral to emerging green technologies such as wind turbines, batteries and photovoltaic cells; technologies that will be crucial in addressing the climate crisis, since the energy sector is the largest single contributor to human greenhouse gas emissions. Our reliance on electronics and the development of renewable energy sources is driving rapid increases in the demand for REEs. However, global production is restricted to relatively few REE deposits, with 90% originating in China. Consequently, there are significant concerns over both the capacity to respond to increased REE demand, and the security of access to these vital resources. Finding new and diverse sources of REEs is therefore essential to maintain our way of life and facilitate our transition to a low-carbon future.The most important sources of REEs are within 'carbonatite' and 'alkaline' igneous rocks. These rocks form deep in the Earth as magmas, which then ascend and solidify at shallower depths, concentrating REEs that eventually become exposed on the Earth's surface. However, the exact formation processes that lead to their enrichment in REEs are poorly understood, and their small size on the surface makes them extremely hard to find. This project will increase our understanding of these rocks, and develop a novel tool to efficiently locate future REE deposits associated with these rock types, using a three-step process.The first step in my research project will develop a computational tool to model how carbonatite and alkaline igneous rocks form. This tool can be used to improve our understanding of, and predict the distribution of, these REE-bearing igneous rocks on Earth.The second step of my research will lay the foundations for locating REE deposits, by analysing the characteristic 'patterns' that their formation leaves on the surrounding geology. When carbonatite and alkaline rocks solidify at shallower depths they alter the surrounding 'country rock', creating alteration zones termed 'fenites'. These fenites have complex structures and textures and are not well understood. By developing a robust understanding of fenites, we can use them as 'signposts' for elusive REE deposits, as the fenite zones are larger and easier to find than the REE-bearing igneous rocks that create them. To accomplish this, I will conduct a detailed study of two well-known fenite zones that exhibit varying structures and textures. By combining structural and chemical observations with my computational models, I will build a holistic understanding of their formation and REE enrichment. This new understanding of the emplacement of REE-bearing igneous rocks and the formation of fenites will enable the final stage of my project: developing new ways of finding REE deposits using remote sensing (airborne) techniques. These techniques, which I will develop alongside industrial partners, will search for fenite zones as signposts for the REE deposits that are associated with them. This methodology is likely to be particularly beneficial in locating REE deposits in hitherto poorly explored, but emerging frontiers, such as the Arctic and East Africa.