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Zarmitan, Charmitan, Guzhumsai |
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Uzbekistan |
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Au Ag
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Super Porphyry Cu and Au
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IOCG Deposits - 70 papers
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All papers now Open Access.
Available as Full Text for direct download or on request. |
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The Zarmitan Goldfield is located in the mountainous Samarkand Province of south eastern Uzbekistan, about 70 km north of the regional centre of Samarkand. The Zarmitan Project is composed of two main mineralised zones which are ~1.5 km apart, Charmitan (to the east) and Guzhumsai (to the west) (#Location: Charmitan - 40° 20' 8"S, 66° 44' 40"E).
The host rocks comprise quartz-mica and carbon-mica sandstones, siltstones and andalusite shale, with rare lenses of carbonates and granosyenite. The main deposits were developed near the contact zone of a late Palaeozoic (269 ± 4.2 Ma) intrusive complex which includes phases of gabbro, syenite, tonalite and granosyenite as well as granite and aplite.
The ore field occurs in a region where the strata are boudinaged in major shear zones. The deposit is composed of a series of fault controlled WNW trending, tabular bodies of linear stockwork and sheeted 'crack-seal' quartz rich veins which contain gold, silver, pyrite, arsenopyrite, scheelite and pyrrhotite, with a gangue of quartz, ankeritic carbonate and sericite, and minor amounts of W, Bi, Pb, Zn and Sb bearing sulphides (Berger, etal., 1994). Mineralisation persists to a depth of 2000 m.
On the basis of mineralogical, fluid inclusion, and stable isotope studies, Bortnikov et al. (1996) proposed that mineralisation resulted from the rapid mixing of magmatic and metamorphic fluids in the aureole of the intrusive complex, deposited at temperatures up to 400° C and pressures up to 2.8 Kbars.
The resulting gold deposit, encompassing both the Charmitan and Guzhumsai orebodies, comprises approximately 30 Mt of ore containing 300 t of gold at a grade of around 10 g/t Au as free milling sulphide bearing laminated quartz veins and, to a minor extent, in refractory arsenious high sulphide ores at the eastern end of the Charmitan deposit which average 8 g/t Au.
The Charmitan deposit alone contains reserves of 210 tonnes of gold, grading 8.7 g/t Au, within a total resource of at least 245 t Au. Using the Uzbekistan reserve classification, as of January 2000, the reserves/resources comprised: C1 - 11.344 Mt @ 10.9 g/t Au, 9.4 g/t Ag for 123.4 t Au; and C2 - 12.863 Mt @ 9.4 g/t Au, 12.1 g/t Ag for 121.805 t Au.
These reserve figures are based on more than 7000 surface drill holes, close spaced sampling of over 133 km of exploratory underground development and >884 000 metres of underground diamond drilling at both Charmitan and Guzhumsai since the discovery of the deposit in the 1960's.
Mining commenced at the Charmitan deposit in 1970 under the control of the State-owned Uzalmazzoloto as a series of open pits, continuing until 1997. Underground mining commenced in 1989 at the rate of approximately 0.1 Mt per annum, with the ore treated at the resin-in-pulp gold plant at Marjanbulak, a separate property located some 85 km to the east.
The most recent source geological information used to prepare this decription was dated: 2004.
This description is a summary from published sources, the chief of which are listed below.
© Copyright Porter GeoConsultancy Pty Ltd. Unauthorised copying, reproduction, storage or dissemination prohibited.
Charmitan
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Abzalov M, 2007 - Zarmitan Granitoid-Hosted Gold Deposit, Tian Shan Belt, Uzbekistan: in Econ. Geol. v102 pp 519-532
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Bortnikov, N.S., Prokofev, V.Y. and Razdolina, N.V. 1996 - Origin of the Charmitan gold-quartz deposit (Uzbekistan): in Geology of Ore Deposits, v38 pp 208-226
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Deng, J., Wang, Q., Li, G., Li, C. and Wang, C., 2014 - Tethys tectonic evolution and its bearing on the distribution of important mineral deposits in the Sanjiang region, SWChina: in Gondwana Research v.26, pp. 419-437.
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Dolgopolova, A., Seltmann, R., Konopelko, D., Biske, Yu. S., Shatov, V., Armstrong, R., Belousova, E., Pankhurst, R., Koneev, R. and Divaev, F., 2017 - Geodynamic evolution of the western Tien Shan, Uzbekistan: Insights from U-Pb SHRIMP geochronology and Sr-Nd-Pb-Hf isotope mapping of granitoids: in Gondwana Research v.47, pp. 76-109.
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Yakubchuk, A.S., Cole, A., Seltmann, R. and Shatov, V., 2002 - Tectonic setting, characteristics and regional exploration criteria for gold mineralization in central Eurasia: The southern Tien Shan province as a key example: in Goldfarb, R. and Nielsen, R., (Eds.) Integrated Methods for Discovery: Global Exploration in Twenty-First Century; Econ. Geol. Special Publication No. 9 pp 177-201
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Porter GeoConsultancy Pty Ltd (PorterGeo) provides access to this database at no charge. It is largely based on scientific papers and reports in the public domain, and was current when the sources consulted were published. While PorterGeo endeavour to ensure the information was accurate at the time of compilation and subsequent updating, PorterGeo, its employees and servants: i). do not warrant, or make any representation regarding the use, or results of the use of the information contained herein as to its correctness, accuracy, currency, or otherwise; and ii). expressly disclaim all liability or responsibility to any person using the information or conclusions contained herein.
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