From arc magmas to ores (FAMOS): A mineral systems approach

从弧岩浆到矿石 (FAMOS)：矿物系统方法

基本信息

批准号：
NE/P017452/1
负责人：
Jamie Wilkinson
金额：
$ 92万
依托单位：
Natural History Museum
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2017
资助国家：
英国
起止时间：
2017 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FP017452%2F1
关键词：
arc magmas ores FAMOS mineral

项目摘要

Society is dependent on a reliable supply of metals and minerals for economic growth, improved standards of living, and development of infrastructure. Population growth means that even with increased recycling and resource efficiency, new mineral deposits still need to be discovered. The efficient exploration for, and discovery of, new resources requires new concepts and new tools. The Mineral Systems approach to exploration considers ore deposits on a lithospheric scale, in terms of the "ingredients", processes and environments that favour their formation. This approach amounts to a "source-pathway-trap" model, with an increased emphasis on predictive capacity, rather than just feature recognition. Historically, much research has focused on the trap, and characterisation of the ore deposits themselves; here we aim to focus deeper in the system by integrating ore deposit formation with concepts of magmatism that arise from igneous petrology and volcanology. Therein lies a challenge because extant models for porphyry systems are increasingly at odds with magmatic models for crustal construction and arc volcanism. Rather than seeing magmatic systems in terms of large, liquid-rich magma chambers, emerging petrological models for crustal magmatism are turning instead to crystal-dominated, volatile-bearing "mushy" systems that traverse most or all of the crust. The dynamics of such systems have important consequences not just for arc magmatism, but also for the chemistry of the volatiles that are exsolved. These same volatiles fuel mineralisation and this is the synergy that we aim to exploit by assembling a multidisciplinary team of researchers from economic geology, igneous and metamorphic petrology, volcanology, geochemistry, numerical modelling and fluid dynamics. Our team embraces almost everyone currently engaged in porphyry mineralisation research in the UK and capitalises on strong existing links between UK ROs and the mining industry, many of who are Project Partners. The research will involve analysis of minerals from a wide variety of mineralised and barren settings using a wealth of modern analytical tools that enable determination of an extensive suite of trace elements and isotope tracers. As each trace element responds to magmatic processes in subtly different ways due to the affinity of different elements for different phases (minerals, melts and fluids), so the multi-element approach affords many advantages over conventional proxies in which the full potential of the Periodic Table is not exploited. The analysis of natural systems will be underpinned by high pressure and temperature experiments to establish the phase relationships of ascending arc magmas and the partition coefficients that capture the affinities of elements for certain phases. As fluid accumulation and migration is an essential, but poorly understood, final step in ore deposit formation, we will develop, in tandem with the geochemistry, numerical models for fluid-bearing mushy systems. Finally, consideration will be given to critical metals that are passengers through the main ore-forming processes, but constitute important, often under-explored, by-products of porphyry mineralisation. The research proposed has a strong element of blue skies investigation, but a particular focus on outcomes that will benefit industry through improved exploration tools. Thus the project bridges the divide between academic and applied research in a way that is not normally possible through industry-funded projects. This bridging activity lies at the heart of the Highlight Topic call, specifically through the integration of new advances in the study of mineral systems, igneous petrology and geochemistry, with a view to identifying conditions that can act as pathfinders for new targets. A key outcome will be a range of trace element proxies that will enable the mining industry to establish the potential fertility of a magmatic arc on local to regional scales.

社会依赖金属和矿物的可靠供应来实现经济增长、提高生活水平和发展基础设施。人口增长意味着即使回收利用和资源效率提高，仍然需要发现新的矿藏。新资源的高效勘探和发现需要新概念和新工具。矿物系统勘探方法根据有利于其形成的“成分”、过程和环境，在岩石圈尺度上考虑矿床。这种方法相当于“源-路径-陷阱”模型，更加强调预测能力，而不仅仅是特征识别。从历史上看，许多研究都集中在圈闭以及矿床本身的特征上。在这里，我们的目标是通过将矿床形成与火成岩石学和火山学产生的岩浆作用概念相结合，更深入地关注该系统。其中存在一个挑战，因为现有的斑岩系统模型与地壳构造和弧火山活动的岩浆模型越来越不一致。新兴的地壳岩浆作用岩石学模型不再将岩浆系统视为大型、富含液体的岩浆室，而是转向以晶体为主、含有挥发物的“糊状”系统，这些系统横贯大部分或全部地壳。这种系统的动力学不仅对电弧岩浆作用产生重要影响，而且对溶解的挥发物的化学性质也产生重要影响。这些相同的挥发物促进矿化，这就是我们的目标，通过组建一个由经济地质学、火成岩和变质岩岩石学、火山学、地球化学、数值模拟和流体动力学的多学科研究人员组成的团队来利用这种协同作用。我们的团队囊括了目前在英国从事斑岩矿化研究的几乎所有人员，并利用英国 RO 与采矿业之间现有的牢固联系（其中许多人是项目合作伙伴）。该研究将涉及使用大量现代分析工具对来自各种矿化和贫瘠环境的矿物进行分析，这些工具能够确定大量的微量元素和同位素示踪剂。由于不同元素对不同相（矿物、熔体和流体）的亲和力，每种微量元素对岩浆过程的响应方式略有不同，因此多元素方法比传统代理方法具有许多优势，在传统代理方法中，周期元素的全部潜力都得到了体现。表未被利用。自然系统的分析将以高压和高温实验为基础，以确定上升弧岩浆的相关系以及捕获元素对某些相的亲和力的分配系数。由于流体积累和运移是矿床形成的最后一步，但人们对此知之甚少，因此我们将与地球化学一起开发含流体糊状系统的数值模型。最后，将考虑主要成矿过程中的关键金属，但它们是斑岩矿化过程中重要的、往往未被充分勘探的副产品。拟议的研究具有很强的蓝天调查元素，但特别关注通过改进勘探工具使工业受益的结果。因此，该项目以一种通常无法通过行业资助的项目实现的方式弥合了学术研究和应用研究之间的鸿沟。这一衔接活动是亮点主题征集的核心，特别是通过整合矿物系统、火成岩岩石学和地球化学研究的新进展，以期确定可以作为新目标探路者的条件。一个关键成果将是一系列微量元素代理，使采矿业能够在局部到区域范围内确定岩浆弧的潜在肥力。