Contrasting Fluids in the Svetlinsk Gold-Telluride Hydrothermal System, South Urals

• Main Authors: Olga Vikent’eva, Vsevolod Prokofiev, Andrey Borovikov, Sergey Kryazhev, Elena Groznova, Mikhail Pritchin, Ilya Vikentyev, Nikolay Bortnikov
• Format: Article
• Language: English
• Published: MDPI AG 2019-12-01
• Series: Minerals
• Subjects: gold-telluride deposit; fluid inclusion; raman spectroscopy; la-icp-ms; native-sulphur-bearing fluid inclusion; hydrothermal fluid; oxygen isotopes
• Online Access: https://www.mdpi.com/2075-163X/10/1/37

The large gold-telluride Svetlinsk deposit (~135 t Au) is considered to be a nontraditional one in the Urals and its origin is debated. A specific feature of the deposit is the abundance of various tellurides, such as tellurides of Fe, Ni, Pb, Sb, Bi, Ag, and Au. The new data of microthermometry, Raman spectroscopy, LA-ICP-MS, and crush-leach analysis (gas and ion chromatography, ICP-MS) for fluid inclusions as well as O-isotope data for quartz were obtained for the construction of PTX parameters of ore-formation and fluid sources in the deposit. Mineralisation was formed at a wide range of temperature and pressure (200−400 °C, 1−4 kbar) and from contrasting fluids with multiple sources. At the early stages, the magmatic fluid evolved during its ascent and phase separation and the fluid derived from the host rock decarbonation and dehydration were involved in the hydrothermal system. In addition, mantle-derived fluid might be involved in the ore-forming process during gold-telluride precipitation as well as heated meteoric waters during the late stages. Early fluids were rich in H₂S, S⁰, and CH₄, while the Au-Te mineralisation was formed from N₂-rich fluid.