Abstract
The Engteri is a new hidden Au-Ag deposit in the Russian segment of the Pacific ore belt. The discovery of this deposit merits special attention, because it involves repeated attempts to reappraise a lowprospective ore occurrence, which were crowned with success as a result of fulfillment of large-scale drilling project. The average Au grade is 18.6 gpt. The deposit is classified as the gold geochemical type of Au-Ag deposits. The major ore mineral is pyrite, which amounts to no less than 95% of the total ore minerals. The native phases comprise electrum and to a lesser extent native gold of low fineness (730). The homogenization temperature of fluid inclusions is 125–255°C with a distinct maximum at 145–150°C. Despite blind localization of some orebodies, the Engteri deposits bears evidence for a deep erosion level: (1) small vertical range of economic mineralization (50–100 m); (2) predominant occurrence of massive sugarlike quartz with a low sulfide content; (3) prevalence of massive and brecciated textures above rhythmically banded textures; and (4) lack of low-temperature propylites. The southern part of the ore field distinguished by occurrence of rhythmically banded, framework-tabular, and brecciated texture has the best prospect for revealing new orebodies. The Engteri deposit allowed us to outline the following prospecting guides and methods of prospecting for hidden Au-Ag deposits: (1) these deposits are regularly arranged in ore clusters between heavy concentrate anomalies of cinnabar and gold-silver or silver-base-metal occurrences (method of missed link); (2) findings of fragments of ore mineral assemblages with sporadically high Au and Ag contents in barren calcite-quartz veins (method of indicators); (3) linear zones of ankeritization in the fields of low- and mediumtemperature propylites (mapping of metasomatic rocks); and (4) pyrite-quartz veinlets with rhythmically banded pockets (mineralogical mapping of halos of stringer-disseminated mineralization).
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References
Barsukov, V.L., Ryzhov, O.B., and Fedorov P.L. Hydrothermal Metasomatic Veins in Shear Fracture Zones, in Teoriya mineralogii (Theory of Mineralogy), Leningrad: Nauka, 1988, pp. 113–120.
Bodnar, R.J. and Vityk, M.O., Interpretation of Microthermometric Data for H2O-NaCl Fluid Inclusions, in Fluid Inclusions in Minerals, Methods and Applications, Blacksburg: Virginia Tech, 1995, pp. 117–130.
Isakovich, I.Z., Oreoly nerudnoi prozhilkovoi mineralizatsii na polimetallicheskikh i zolotorudnykh mestorozhdeniyakh i ikh prognozno-poiskovoe znachenie (Halos of Barren Veinlet Mineralization at Base-Metal and Gold Deposits and Their Implications for Forecasting and Prospecting), Moscow: Borodino-E, 2009.
Konstantinov, M.M., Zolotoe i serebryanoe orudenenie vulkanogennykh poyasov mira (Gold and Silver Mineralization in Volcanic Belts of the World), Moscow: Nedra, 1984.
Konstantinov, M.M. and Struzhkov, S.F., Application of Indicator Halos (Signs of Ore Remobilization) in Exploration for Blind Gold and Silver Deposits, J. Geochem. Explor., 1995, vol. 54, pp. 1–17.
Mnogofaktornye prognozno-poiskovye modeli mestorozhdenii zolota i serebra Severo-Vostoka Rossii (Multifactor Forecasting and Prospecting Models of Gold and Silver Deposits in the Russian Northeast), Konstantinov, M.M. et al., Eds., Moscow, 1992.
Natalenko, M.V., Struzhkov, S.F., Ryzhov, O.B., et al., Geology and Mineralogy of Ores in the Birkachn Deposit, Magadan Region, Rudy Met., 2002, no. 6, pp. 37–52.
Nenasheva, S.N. and Godovikov, A.A., A Subsolidus Part of the AgSbS2-PbS, in Eksperimental’nye issledovaniya po mineralogii (1960–1970 gg.) (Experimental Studies in Mineralogy, 1960–1970), Novosibirsk, 1971, pp. 39–46.
Obushkov, A.V., Pockets of Ore Mineralization in Postore Quartz-Calcite Veins As a Guide for Hidden Orebodies at Au-Ag Deposits, in VIII mezhdunar. konf. “Novye idei v naukakh o Zemle” (Proceedings of VIII Intern. Conf., New Ideas in Earth Sciences), Moscow: Russian State Geol. Prospecting Univ., 2006, vol. 5, pp. 179–181.
Omel’yanenko, B.I., Volovikova, I.M., Drits, V.A., et al., A Matter of Term Sericite, Izv. Akad. Nauk SSSR, Ser. Geol., 1982, no. 5, pp. 69–87.
Ryzhov, O.B., Struzhkov, S.F., Aristov, V.V., et al., Geology and Ore Composition of the Julietta Gold-Silver Deposit, Rudy Met., 1995, no. 2, pp. 66–78.
Savva, N.E., Mineralogical Features of Gold and Silver Mineralization in the Omsukchan District, the Northeast of the USSR, Cand. Sci. (Geol.-Mineral.) Dissertation, Moscow: Moscow State Univ., 1980.
Sidorov, A.A., Konstantinov, M.M., Eremin, R.A., et al., Serebro (geologiya, mineralogiya, genezis, zakonomernosti razmeshcheniya mestorozhdenii) (Silver: Geology, Mineralogy, Genesis, and Localization), Moscow: Nauka, 1989.
Sillitoe, R.H., Exploration and Discovery of Base- and Precious-Metal Deposits in the Circum-Pacific Region During the Last 25 Years, Resource Geology Special Issue, 1995, no. 19.
Sillitoe, R.H., Exploration and Discovery of Base- and Precious-Metal Deposits in the Circum-Pacific Region - a Late 1990s Update, Resource Geology Special Issue, 2000, no. 21.
Simpson, M.P. and Mauk, J.L., The Favona Epithermal Gold-Silver Deposit, Waihi, New Zealand, Econ. Geol., 2007, vol. 102, pp. 817–839.
Smirnov, V.I., Geologiya poleznykh iskopaemykh (Geology of Mineral Resources), Moscow: Nedra, 1976, the 3rd Ed.
Struzhkov, S.F. and Konstantinov, M.M., Metallogeniya zolota i serebra Okhotsko-Chukotskogo vulkanogennogo poyasa (Metallogeny of Gold and Silver in the Okhiotsk-Chukotka Volcanic Belt), Moscow: Nauchnyi Mir, 2005.
Struzhkov, S.F., Ryzhov, O.B., Aristov, V.V., et al., Geological Structure and Ore Mineralogy of the Julietta Gold-Silver Deposit, Northeast Russia, Intern. Geol. Rev., 1996, vol. 38, pp. 625–648.
Struzhkov, S.F., Aristov, V.V., Danil’chenko, V.A., et al., Otkrytie mestorozhdenii zolota Tikhookeanskogo rudnogo poyasa (1959–2008 gg.) (Discovery of Gold Deposits in the Pacific Ore Belt, 1959–2008), Moscow: Nauchnyi Mir, 2008.
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Original Russian Text © A.V. Obushkov, S.F. Struzhkov, M.V. Natalenko, O.B. Ryzhov, S.G. Kryazhev, Yu.I. Radchenko, 2010, published in Geologiya Rudnykh Mestorozhdenii, 2010, Vol. 52, No. 6, pp. 512–533.
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Obushkov, A.V., Struzhkov, S.F., Natalenko, M.V. et al. Geology and mineralogy of ore at the hidden Engteri Au-Ag deposit, the Magadan Region. Geol. Ore Deposits 52, 459–478 (2010). https://doi.org/10.1134/S1075701510060036
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DOI: https://doi.org/10.1134/S1075701510060036