Mineral composition of ores of the Parnok ferromanganese deposit (Polar Urals, Russia)

A detailed description of the mineral composition of ores of the Parnok fer romanganese deposit(1) in the Polar Urals is presented. The mineral and com mercial ore types, as well as the typical mineral paragenetic associations, are identified. It is shown that carbonate and silicate-carbonate ores are the primary varieties, with the major minerals being rhodochrosite, rhodon ite, tephroite, and some others. The evidence for their hydrothermal-sedime ntary genesis of Red Sea type manganese deposits is cited. The lenticular-b edded, strata-bound ore lodes are indicative of this. The impact of catagen ic and metamorphic processes on ores defined the presence of the spessartit -rhodonite, -parsettensite paragenesis and the development of schistose and augen ore textures. The secondary oxidized ores, of Mesozoic-Cenozoic (up to Modern) age form linear and adjacent linear-bedded zones. They are mainl y composed of nsutite, cryptomelane, and pyrolusite. The most valuable pero xide varieties, with MnO2 > 42% and (MnO2/MnO) > 1.3, are also present amon g the oxidized ores. Data on the composition of iron ores alternating with manganese varieties are given. Magnetite, the major mineral of the iron ore s, associates with greenalite, stilpnomelane, siderite, and calcite. Some s imilar features of the Parnok deposit with other deposits of the Urals, as well as Kazakhstan, Japan, the USA, and Sweden, are pointed out. However, t he ores of the Parnok deposit, in contrast to the latter, are free of jaspe r rocks.