ИСТИНА

Six paragenetic stages are distinguished on the basis of mineralogy and textural relationships at the Novonikolaevskoe deposit (South Urals): magmatic, skarn, post-skarn, sulfide-oxide, sulfide-telluride, and supergene. Productive mineralization is mainly associated with sulfide-oxide and sulfide-telluride stages. The sulfide-oxide stage includes quartz-chlorite alterations and the formation of pyrite, magnetite and cassiter-ite. The sulfide-telluride stage is related to quartz-carbonate-sericite alteration and the formation of various sul-fides and tellurides. Cassiterite, coloradoite, and tsumoite are found for the first time at the Novonikolaevskoe deposit using scanning electron microscopy and electron probe microanalysis.