Bismuth Mineralization of the Belogorskoe Magnetite Deposit (Sikhote-Alin).

The orebodies of the Belogorskoe deposit contain various bismuth minerals. Many of them are rare in nature or are rare mineral varieties. Among them are native bismuth, bismuthine, cosalite, gladite (?), jonassonite, a galenobismuthite variety enriched in Ag and Cu, bismite, bismutite, preisingerite, bismoclite, zavaritskite, and a large group of unnamed compounds. One specific feature of the endogenous bismuth mineralization of the deposit is its localization in the low- to medium- temperature hydrothermal alteration products of the early assemblages, especially in large carbonate (with fluorite) pockets in blocks of essentially magnetite ores, where it is closely associated with Au–Ag–Pd–Pt and Mo–W mineralization. A significant amount of Ag in the form of Ag–Bi minerals is also related with the bismuth mineralization of the Belogorskoe deposit. The close geochemical relationship of Bi, Au, and PGE in the processes of mineral formation at the Belogorskoe deposit is also manifested by the presence of the common minerals of these elements, such as jonassonite and the unnamed compound Ru(Pb,Ag)2Bi4. The association of bismuth and molybdenum–tungsten mineralization is a characteristic feature of the ores of some tungsten and molybdenum skarn deposits containing scheelite, molybdenite, and bismuthine as the main minerals. The presence of bismuth and noble-metal mineralization is most characteristic of gold and complex gold-bearing ores of hydrothermal deposits of various types. However, such metals as W, Mo, and Bi, as well as Au, Ag, Pd, and Pt, have no independent industrial role at the Belogorskoe deposit, unlike the deposits of the above-mentioned types, and are accompanying useful components relative to iron ores. Rocks and ores that compose the orebodies of the Belogorskoe deposit are Triassic metalliferous sediments that accumulated in island lagoons as a result of erosion of the lateritic weathering crust of ancient gabbroids, which were metamorphosed and partially regenerated during the Late Cretaceous. This accounts for the enrichment of ores in various metals, including Fe and Mn, and the presence of gold–silver–palladium–platinum, nickel–cobalt, and bismuth mineralization, which (including Bi compounds with Au and PGE) is characteristic of some ultramafic massifs. [ABSTRACT FROM AUTHOR]