GOLD-RARE-METAL MINERALIZATION OF THE MOKRUNDYA PLACER DEPOSIT (Arctic Siberia, Republic of Sakha (Yakutia))
E.V. Airiyants1, D.K. Belyanin1,2, S.M. Zhmodik1, P.O. Ivanov3, O.N. Kiseleva1
1V.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
2Novosibirsk State University, Novosibirsk, Russia
3Arctic Capital LLC, Yakutsk, Russia
Keywords: Gold-bismuth-telluride mineralization, native gold, maldonite, northeast of the Republic of Sakha
Abstract
The Mokrundya alluvial gold placer deposit is located in the Verkhoyansk-Kolyma folded region, within the Tuguchak ore-placer cluster. Using ore and scanning electron microscopy and chemical-analysis methods, we have studied the typomorphic, mineralogical, and geochemical features of gold, minerals of the heavy fraction of the placer, and ore mineralization of the dolerite dike complex stripped in the placer bedrock. The stages of development of the ore-forming system in dolerites have been established. The main productive stages with native gold are associated with the postmagmatic stage: (1) early arsenopyrite-polysulfide stage and (2) gold-bismuth-telluride stage. The gold-bismuth-telluride stage includes bismuth tellurides and sulfotellurides, native gold, bismuth, maldonite AuBi2, and complex intermetallic compounds of Au and Bi. We hypothesize about the sources of placer gold in alluvial deposits, one of which is the ore mineralization of the dolerite dike complex, and the other is associated with the mineralized zones of the Gematitovoe skarn-hydrothermal ore occurrence localized in the upper reaches of the Mokrundya Brook.
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