The Gorevskoe Giant Zinc–Lead Deposit, Yenisei Ridge, Russian Federation

The Gorevskoe zinc–lead deposit is located within the Angara-Bolshepit mineragenic zone of the Altai-Sayan province. The ore-host geological section containing polymetallic ores is characterized by a heterogeneous composition of its constituent sedimentary rock differences and is represented locally, at the deposit site, by manganese-containing siderite (50 vol %), siliceous siderite (30 vol %), silicite (5 vol %), dolomite, mudstone, siltstone, and marl, and regionally mainly by limestone, metasiltstone, and manganese–containing and siliceous siderite. The deposit is located within the zones of regional metamorphism and is characterized by the development of garnet–tremolite–actinolite and cummingtonite–grunerite assemblages. The ores have veined-impregnated, breccia-like, banded textures, rarely massive and relict layered ones; their diverse combination reflects the complex history of the ore formation process. In the ores, there are several generations of the main ore-forming minerals, composing a number of paragenetic mineral associations of different ages: 1) pyrite–pyrrhotite–sphalerite–galena, 2) sphalerite–pyrrhotite–galena with pyrite, 3) quartz–galena with sphalerite, 4) quartz–sphalerite–galena with pyrite and pyrrhotite, and 5) pyrite–pyrrhotite–magnetite with sphalerite and galena. As a result of the generalization of data on the study of the isotopic composition of sulfur, carbon and oxygen, it was found that a characteristic feature of all sulfides of ores of the deposit is their significant enrichment with heavy isotope 34S; variations in the isotopic composition of C and O of ore-bearing carbonate rocks are small and close to calcite of marine sediments; carbonates of ores have comparatively light isotopic compositions, especially carbon, which mainly corresponds to the mantle reservoir in terms of isotopic composition. The hydrothermal–sedimentary nature of primary ore accumulations and their subsequent transformation during high-grade regional metamorphism are proved.