Material composition of the inter-ore shales of Kursk series has been studied within three different iron ore deposits of the Kursk block of Voronezh crystalline core-area. The noble-metal enrichment of their most sulfidized varieties was found. Pyrite and pyrrhotite predominate among the sulphides are represented by different morphological types. In the gravity concentrate of bulk mineral shale samples, special methods of enrichment, electron-microscopical analysis show the presence of native gold as well as noble-metal containing tellurides, bismuthides, sulphoarsenides, in association with a wide range of sulfides. The study of the isotopic composition of lead in sulfide minerals of various morphogenetic types indicates Proterozoic age of sulphide mineralization (tM = 1,51-2,235 billion years), with upper crust source (μ = 10,1-10,9). The similarity in isotope characteristics of lead in both diagenetic and imposed sulfides may be indicative of long-term interaction and deep isotope exchange between the oreforming fluids and host rocks. The established mineral associations of chalcophilic specialization (native gold, tellurides, bismuthides of gold and silver with palladium) are most typical for epi-and mesothermal gold deposits of hydrothermal and metamorphic-hydrothermal origin. Thus, the mine ralogical and isotopic-geochemical studies indicate the major role of metamorphic-hydrothermal processes in the formation of noble-metal mineralization.
|Журнал||ВЕСТНИК САНКТ-ПЕТЕРБУРГСКОГО УНИВЕРСИТЕТА. СЕРИЯ 7: ГЕОЛОГИЯ, ГЕОГРАФИЯ|
|Состояние||Опубликовано - 1 янв 2014|
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