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Rustam Koneev, National University of Uzbekistan named after Mirzo Ulugbek (Uzbekistan)
Nigel Cook, Natural History Museum, University of Oslo (Norway)
Cristiana Ciobanu, University of Adelaide (Australia)
Yulia Mun, National University of Uzbekistan named after Mirzo Ulugbek (Uzbekistan)
Rustam Khalmatov, National University of Uzbekistan named after Mirzo Ulugbek (Uzbekistan)
Alexander Jukov, National University of Uzbekistan named after Mirzo Ulugbek (Uzbekistan)
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Gold and gold-silver deposits of Uzbekistan can be sub-divided into gold-quartz, gold-sulphide-quartz and gold-sulphide types. They are located within the Beltau-Kuraminsky volcano-plutonic belt (BKVPB), within the Kyzylkumsky, Nuratinsky, Kuraminsky and Chatkal ore camps. They form regular series of deposits within certain ore formations according to the pattern: /Au-W/Au-As/Au-Te/Au-Ag/Au-Sb/Au-Hg/, and are distributed in "black slates", terrigene-sedimentary and other rock units. In all cases the rocks are propylitized, beresitized and argillized. The deposits of the various ore formations within the BKVPB range are distributed in a zoned fashion. In the western part (Kyzylkumsky and Nuratinsky), the economic resource is determined by Au-W and Au-As formations, with Au-Te, Au-Ag, Au-Sb, Au-Hg mineralization being of secondary value. These include the Muruntau, Kokpatas, Charmitan, Gujumsay deposits. In the Kuraminsky region, Au-Te and Au-Ag deposits (Kochbulak, Kyzylalmasay) dominate, but in the Chatkal region, Au-Sb and Au-Hg deposits (Kadamjai, Haidarkan) are most abundant. In the large poorly-eroded deposits, or in orefields in which the full tectonostratigraphic sequence is well preserved, a characteristic vertical geochemical zoning (from bottom to top) may be readily recognized. The regularity of zonation is clearly reflected in the distribution and composition of tellurides and selenides within the ores. Tellurides and selenides of bismuth are common in Western Uzbekistan, in, for example, the Muruntau, Muytenbay, Charmitan and Gujumsay deposits. Selenide and tellurides of silver and gold, and especially tellurides of Sb, Hg and Pb are most abundant in Eastern Uzbekistan (Kochbulak, Kayragach, Kyzylalmasay and Chadak). Selenides of bismuth or silver are common at upper levels, but their abundance, and the role of selenium, decreases with depth. Conversely, the role of Ag-, Au-, Hg-, Sb-, Pb- and Bi-tellurides increases markedly with depth. The tellurides and selenides form regular microparageneses or so-called "nanoensembles" within the specific types of mineralization or at certain levels of the deposits. The revealed distributions of the tellurides and selenides, and their tendencies towards a spatially-governed speciation within zoned deposits allow us to use them when defining type of mineralization, zoning level and degree of erosion. Identification and mapping of telluride-selenide parageneses can greatly assist in exploration for hidden gold or gold-silver mineralization.
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