Magmas, fluids, faults & metals - re-assessing the controls on magmatic-hydrothermal mineralisation & zonation associated with the Cornubian Batholith

岩浆、流体、断层

• 批准号: 2580988
• 金额: --
• 依托单位: UNIVERSITY OF EXETER
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2580988
• 关键词: Magmas; fluids; faults; metals; re

Full project title: Magmas, fluids, faults and metals - re-assessing the controls on magmatic-hydrothermal W-Sn-Cu-As-Zn-Pb mineralisation and zonation associated with the Cornubian Batholith, SW England.The W-Sn-Cu-As-Zn-Pb ore field, centred upon the Early Permian Cornubian Batholith, is a global exemplar of magmatic-hydrothermal mineralisation associated with peraluminous granites and mineral zonation, where there is often a progressive change in dominant mineral assemblage with distance from the granite (W-Sn plus/minus As proximal and Cu, Zn and Pb distal). The heterogeneous distribution of metals and mineralisation styles around "emanative centres", including the anomalous occurrence of substantial Cu with peraluminous granite, indicates a complex relationship between magmatism, separation of magmatic volatile phases, faulting and fluid mixing. Changes in source melting and differentiation control the broad distribution of granite types and metal prospectivity (Simons et al., 2017). The focus of this project is to characterise the fluid types involved in mineralisation and how their structurally-controlled migration and mixing has controlled variations in the distribution of mineral assemblages and metals.Project Aims and MethodsThe project is focussed upon the systematic analysis of melt and fluid inclusions in different granite types and mineralisation styles from across the SW England orefield. These will be used to determine: (1) the compositional variability of primary exsolved magmatic-hydrothermal fluids and their control by evolving melt compositions, and (2) the parameters controlling precipitation of ore metals from these solutions (e.g. cooling, phase separation, wall-rock reaction). Careful sample mineralogy and petrography, including SEM, QEMSCAN and cathodoluminescence techniques, will underpin the fluid inclusion microanalysis using microthermometry and laser ablation ICP-MS. Isotopic analysis of minerals will be used to evaluate alternative models for the source and evolution of fluids. These data will be combined with the distribution of syn-magmatic fault systems and historical metal production, to provide a re-evaluation of the controls on mineralisation, mineral zonation and the origin of "emanative centres". The project will utilise material from collections at the Natural History Museum, Imperial College London and Camborne School of Mines but will require fieldwork to collect samples from areas where cross-cutting relationships between intrusions and vein sets can be documented in detail. Current and recent exploration by the CASE partners has provides an unparalleled opportunity to sample from diamond drill core samples.

项目完整名称：岩浆、流体、断层和金属 - 重新评估对英格兰西南部 Cornubian 基岩相关的岩浆热液 W-Sn-Cu-As-Zn-Pb 矿化和分带的控制。W-Sn-Cu -As-Zn-Pb 矿田以早二叠世 Cornubian 基岩为中心，是与过铝矿相关的岩浆-热液成矿的全球典范花岗岩和矿物分带，其中主要矿物组合通常随着距花岗岩的距离而逐渐变化（W-Sn 加/减 As 近端和 Cu、Zn 和 Pb 远端）。 “喷发中心”周围金属和矿化类型的不均匀分布，包括大量铜与过铝质花岗岩的异常出现，表明岩浆作用、岩浆挥发相分离、断层和流体混合之间存在复杂的关系。源头熔化和分异的变化控制着花岗岩类型和金属前景的广泛分布（Simons等，2017）。该项目的重点是表征矿化中涉及的流体类型，以及它们的结构控制的迁移和混合如何控制矿物组合和金属分布的变化。项目目标和方法该项目的重点是熔体和流体的系统分析英格兰西南部矿田不同花岗岩类型和矿化风格的包裹体。这些将用于确定：（1）初级溶出的岩浆热液的成分变化及其通过演化熔体成分的控制，以及（2）控制矿石金属从这些溶液中沉淀的参数（例如冷却、相分离、壁） -岩石反应）。仔细的样品矿物学和岩相学，包括 SEM、QEMSCAN 和阴极发光技术，将支持使用显微测温和激光烧蚀 ICP-MS 进行流体包裹体微量分析。矿物的同位素分析将用于评估流体来源和演化的替代模型。这些数据将与同岩浆断层系统的分布和历史金属生产相结合，以重新评估对矿化、矿产分带和“喷发中心”起源的控制。该项目将利用自然历史博物馆、伦敦帝国理工学院和坎伯恩矿业学院收藏的材料，但需要进行实地工作，从可以详细记录侵入物和矿脉之间交叉关系的区域收集样本。 CASE 合作伙伴当前和最近的勘探为从金刚石钻芯样本中取样提供了无与伦比的机会。