K. A. Novoselov

Mineralogy and formation conditions of ores in the Bereznyakovskoe ore field, the Southern Urals, Russia

AbstractThe Bereznyakovskoe ore field is situated in the Birgil’da-Tomino ore district of the East Ural volcanic zone. The ore field comprises several centers of hydrothermal mineralization, including the Central Bereznyakovskoe and Southeastern Bereznyakovskoe deposits, which are characterized in this paper. The disseminated and stringer-disseminated orebodies at these deposits are hosted in Upper Devonian-Lower Carboniferous dacitic-andesitic tuff and are accompanied by quartz-sericite hydrothermal alteration. Three ore stages are recognized: early ore (pyrite); main ore (telluride-base-metal, with enargite, fahlore-telluride, and gold telluride substages); and late ore (galena-sphalerite). The early and the main ore stages covered temperature intervals of 320–380 to 180°C and 280–300 to 170°C, respectively; the ore precipitated from fluids with a predominance of NaCl. The mineral zoning of the ore field is expressed in the following change of prevalent mineral assemblages from the Central Bereznyakovskoe deposit toward the Southeastern Bereznyakovskoe deposit: enargite, tennantite, native tellurium, tellurides, and selenides → tennantite-tetrahedrite, tellurides, and sulfoselenides (galenoclausthalite) → tetrahedrite, tellurides, native gold, galena, and sphalerite. The established trend of mineral assemblages was controlled by a decrease in

Mineralogy and formation conditions of ore from the Biksizak silver-base-metal occurrence in the South Ural, Russia

f_{S_2 }

Mineralogy of alluvial sediments of Avzyan gold region (the Southern Urals)

,

Silver sulfoselenide from ore of the Valunisty Au-Ag deposit, Chukchi Peninsula

f_{Te_2 }

Supergene sulphides and related minerals in the supergene profiles of VHMS deposits from the South Urals

and