How 'orogenic' is orogenic gold? Clues from the Scottish Grampian Terrane

苏格兰格兰扁地体是进行详细研究的理想之地：地质学相对较为人所知，而且通常很容易进入。已知有几个贵金属矿点，但它们与岩浆和变形事件的成因关系尚不清楚。金以碎屑金和石英脉的形式广泛分布。到目前为止，只有一个矿脉系统（廷德鲁姆附近的Cononish）已开发用于生产，而该地区的其他地区仍然严重缺乏研究。尽管在北方爱尔兰的格兰扁发现了Cononish、Cavanacaw和Curraghinalt，但苏格兰重要金矿化的潜力仍普遍被低估。复杂造山带的成矿研究需要综合利用结构、地球化学和地球物理方法的数据。矿石和矿化研究小组（OMG：https：//www.facebook.com/OMGLeeds; Twitter @OMGLeeds）涵盖了这些分支学科，包括OMG开发的一种方法，该方法使用金微化学来区分造山热液金和岩浆热液金。与持有勘探许可证的公司建立了良好的关系，可以获得油田、地质和地球物理数据和样本以及以前的勘探活动结果。作为NERC DTP学生，您可以访问同位素实验室（例如格拉斯哥的SUERC）。OMG以前的工作提供了重要的背景和支持，包括正在进行的苏格兰、北方爱尔兰、爱尔兰和纽芬兰的喀里多尼亚地区的黄金博士研究。矿脉矿化的新发现表明该地区的矿物学比以前认识到的更复杂。附近的侵入体表明，一些矿化可能与岩浆作用有关。该项目结合了强大的结构理解，金颗粒矿物学和微量化学，以及放射性测年。结构工作得到了行业合作者获得的新的地面磁力数据的支持。您将有机会进行更区域性的研究，将格兰扁构造演化与碎屑金的成分调查相结合，以阐明区域成矿作用。主要目标是：1.侵入岩和矿脉的特征，包括它们与断层骨架的关系;2.矿化和侵入岩的稳定同位素和年代学研究;3.地球物理研究（磁力测量）;碎屑金的成分研究。预期结果将是矿床的成因模型，解决i）结构演化; ii）岩浆活动; iii）矿化年龄之间的联系。特别关注的是区分“造山”和岩浆特征，以及矿床是否可以承载几个与造山和岩浆系统重叠的金矿化事件。一个可论证的多期存款演化将对全球造山带金存款成因模式的争论做出重要贡献。

The Scottish Grampian Terrane is ideal for a detailed study: the geology is relatively well known and access generally easy. Several precious metal occurrences are known, but their genetic relationship to magmatic and deformation events is unclear. Gold is widespread both as detrital gold and in quartz veins. To date, only one of these vein systems (Cononish near Tyndrum) has been developed towards production, whilst the rest of the area remains severely under-researched. The potential of significant gold mineralisation in Scotland is generally still under-appreciated despite the discovery of Cononish, and of Cavanacaw and Curraghinalt in the Grampian of Northern Ireland.Studies of mineralisation in complex orogenic belts requires a holistic approach combining data from structural, geochemical and geophysical approaches. The Ores and Mineralisation Research Group (OMG: https://www.facebook.com/OMGLeeds; Twitter @OMGLeeds) covers these subdisciplines, including a method, developed at OMG, of using gold microchemistry to discriminate orogenic from magmatic hydrothermal gold. Excellent relationships with companies holding exploration licences provides access to field areas, geological and geophysical data and samples, and previous exploration campaign results. As a NERC DTP student, you have access to isotope laboratories (e.g. SUERC in Glasgow). Previous work at OMG provides crucial background and support, including ongoing PhD studies of gold in the Caledonian terranes of Scotland, Northern Ireland, Ireland, and Newfoundland.You will focus on Aberfeldy - Crieff areas. New discoveries of vein mineralisation point to a more complex mineralogy within the area than previously appreciated. Nearby intrusive bodies suggest that some of the mineralisation may be linked to magmatism. The project combines a robust structural understanding, gold particle mineralogy and microchemistry, and radiometric dating. Structural work is supported by new ground magnetic data acquired by the industry collaborator. You will have an opportunity to pursue a more regional study combining Grampian tectonic evolution with a compositional survey of detrital gold to illuminate regional metallogeny. The main objectives are:1. Characterisation of intrusives and veins, including their relationships to the fault framework;2. Stable isotope and geochronological studies of mineralisation and intrusives;3. Geophysical studies (magnetic surveys); and4. Compositional studies of detrital gold.The expected result will be a genetic model for the deposits, addressing the linkage between i) the structural evolution; ii) magmatic activity; and iii) age of mineralisation. Special focus will be on distinguishing between 'orogenic' and magmatic signatures, and whether the deposits could host several gold mineralisation events overlapping both orogenic and magmatic systems. A demonstratable multi-phase deposit evolution will be an important contribution to the global debate of gold deposit genetic models in orogenic belts.