Sulphur and lead isotope systematics of the Cononish Au-Ag-Te deposit, Scotland

摘要

The genesis of 'orogenic', vein-hosted gold mineralisation in metamorphic belts is controversial. The Con-onish Au-Ag-Te deposit is no exception. Situated in the mining district of Tyndrum, it has become Scotland's first ever commercial gold mine with a current resource of 266 koz Au and 1096 koz Ag. Ore consists of a series of hydrothermal quartz ± carbonate veins that occupy an anastomosing, transtensional fault zone striking NE-SW - sub-parallel to the nearby Tyndrum Fault (Treagus et al. 1999). Mineralisation crosscuts deformed (D1-D4) stratigraphy of the Dalradian Supergroup; metamorphosed to epidote-amphibolite facies ~470 Ma (Stephenson et al. 2013). Whilst Con-onish displays broad commonalities with the orogenic group of ore deposit (Goldfarb et al. 2005), K-feldspar alteration in an auriferous breccia yield Ar/Ar ages of 408 ± 2 Ma and 407 ± 1 Ma (Rice et al. 2013). This links mineralisation to the main episode of shear-modulated, post Caledonian magmatism in the Grampian belt (Miles et al. 2016).