Prediction of the type of gold deposits according to the native gold mineralogy of the Verkhneamginskaya area (Yakutia)
Nikiforovа Z. S., Anisimova G. S., Sokolov E. P., Kazhenkina A. G.
Zapiski RMO (Proceedings of the Russian Mineralogical Society). 2021. V. 150. N 1. P. 30-47
The Khatyrkhay ore-placer cluster is located in central part of the Verkhneamginskaya goldbearing area of the Aldan-Stanovoy metallogenic province. Mineralogical-geochemical features of placer gold of the Tayakhtakh, Gorel, Krutoy creeks and ore minerals of gold occurrences of the Khatyrkhay ore-placer cluster have been studied with purpose to determine the types of primary gold deposits. In general, it was found that, by typomorphic features, native gold belongs to a single type and is represented mainly by fine fraction particles (0.1–0.25 mm) with hemi-euhedral forms, high fineness, coarse- and medium-grained structure. Discovery of elements of platinum group, as well as an increased content of Cu, Fe and Bi, microinclusions of tellurobismuthinite, galenobismuthinite, galena, chalcopyrite indicate that gold-skarn bodies, connected with exocontact zones of intrusions and syenite dikes are primary sources of native gold. Mineralogical-geochemical features of placer gold and mineralogy of primary ore in Khatyrkhay ore-placer cluster allowed to determine indicators of placer and ore gold for this gold-skarn deposits. Comparison of typomorphic features of gold from placers and primary ores in mineralized zones of Khatyrkhay cluster with gold from the Central Aldan deposits enabled us to prove that, primary sources are represented by gold-skarn type of mineralization (Lebedinsky type), developed in skarn-altered rocks and berezitized granite-gneisses. Distribution of placer gold in Tayakhtakh, Gorely and Krutoy creek basins testifies that primary sources, related to skarn-forming processes, occur in near-contact zones of intrusions (granite-gneisses and syenites) and host dolomites, which are spread through the Khatyrkhay ore-placer cluster, that provides a base for large area of spreading of the lebedinsky type gold mineralization.
Keywords: placer gold, microinclusions, mineralogical and geochemical indicators, ore-placer cluster, prediction, gold deposits