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

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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.