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GEOCHEMICAL PECULIARITIES AND ORE CONTENT OF CARBON-BEARING SEDIMENTS OF THE AMAZARKANSKY GOLD DEPOSIT (EASTERN TRANSBAIKALIA)

B. N. Abramov, R. A. Filenko, T. G. Tsyrenov

Institute of Natural Resources, Ecology and Cryology SB RAS, Chita, Russia

The Amazarkanskoye deposit is confined to the intersection node of the northeastern fault zone with tectonic dislocations of sublatitudinal, northwestern and submeridional directions. The Severnaya and Shirotnaya ore zones with vein-embedded stockwork-type mineralization are distinguished. Carbon-bearing sediments are represented by gneisses of the Paleo-Proterozoic Amazar Formation (AR2am), they are gravitated by zones of vein and disseminated mineralization. Gneisses are characterized by elevated gold contents from 0.05 g/t to 2.54 g/t. In terms of the organic carbon content they correspond to high carbonaceous gneisses. Shales of the Amazar Formation correspond to the terrigenous-carbonaceous formation. They were accumulated in shallow epicontinental basins or in the shelf zone in an island-arc environment. The carbon isotopic composition of graphite inclusions in quartz veins indicates its biogenic nature. It was concluded that carbonaceous gneisses of the Amazar Formation were one of the sources of gold ore mineralization.

Keywords: Amazarkanskoye deposit, carbon-bearing gneisses, gold, carbon isotopes, sources of mineralization, Eastern Transbaikalia.

DOI 10.20403/2078-0575-2024-3-74-83

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