The mineralogical and geochemical peculiarities and formation conditions of gold are considered for the Kopto gold stockwork deposit juxtaposed on skarns and metasomatites of the Tardan gold cluster (Northeast Tuva). Gold mineralization is confned to granite-porphyry dikes of the Early Ordovician Early Tannuola complex and associated beresite-listvenite metasomatites. In composition of productive mineral assemblage, the Kopto with electrum, acanthite, native bismuth and barite deposit belongs to gold-pyrite-chalcopyrite type. The fneness of native gold varies from 969 to 524 (802, on average). According to the fuid inclusion data, the gold-sulfde-quartz veins were formed at 230-165 °C from NaCl–H2O, NaCl-KCl–H2O and MgCl2–H2O fuids with salinity of 4-8 wt. % NaCl equiv.

Figures 4. Tables 1. References 14.

Key words: native gold, gold deposits, quartz, Tuva.

R.V. Kuzhuget, Tuvinian Institute for Exploration of Natural Resources SB RAS, ul. Internatsional’naya 117a, Kyzyl, 667007 Russia; rkuzhuget@mail.ru

N.N. Ankusheva, Institute of Mineralogy UB RAS, Miass, 456317 Russia; ankusheva@mail.ru

Sh.N. Oorzhak, Tuvinian Institute for Exploration of Natural Resources SB RAS, ul. Internatsional’naya 117a, Kyzyl, 667007 Russia;

Yu.V. Butanaev,Tuvinian Institute for Exploration of Natural Resources SB RAS, ul. Internatsional’naya 117a, Kyzyl, 667007 Russia

1. Borisenko A.S. (1977) [Study of salinity of fuid inclusions in minerals using cryometry]. Geologiya i geofzika, 8, 16-28 (in Russian).
2. Bodnar R.J., Vityk M.O. (1994) Interpretation of microthermometric data for H2O–NaCl fuid inclusions. Fluid inclusions in minerals: methods and applications. Pontignana-Siena, 117-130.
3. Ermakov N.P. (1972) [Geochemical systems of inclusions in minerals]. Moscow, Nedra, 376 p. (in Russian).
4. Kilchichakov K.M., Tokunov V.F., Plekhanov A.I. (1966) [Results of evaluation of the Tardan gold deposit and prospecting for gold in the Bai-Syut River basin]. Kyzyl, 150 p. (in Russian).
5. Kilchichakov K.M., Plekhanov A.M., Katsapov A.N. (1977) [Prospecting for gold in the area of the Tardan deposit]. Kyzyl, 139 р. (in Russian)
6. Kuzhuget R.V., Zaikov V.V., Lebedev V.I., Mongush A.A. (2015) [Gold mineralization of the Khaak-Sair gold-quartz ore occurrence in listwänites (Western Tuva)]. Russian Geology and Geophysics, 9, 1332-1348.
7. Kuzhuget R.V., Prokopyev I.R., Redina A.A. (2018) [Mineralogical-geochemical features and PTX formation conditions of the Tardan-2 gold-sulfde-quartz occurrence (Northeast Tuva)]. Geologiya, magmatizm i metallogeniya Central’noy Azii. 2018: Rudno-magmaticheskie sistemy Sangilena (shchelochnye intruzivy karbonatity): Materialy I Vserossiyskoy polevoy konferentsii s mezhdunarodnym uchastiem [Geology, magmatism and metallogeny of Central Asia. 2018: Ore-magmatic systems of Sangilen (alkaline intrusives, carbonatites): Proceedings of the frst All-Russian feld conference with international participation]. Kyzyl, TuvIENR SB RAS, 53-57. (in Russian).
8. Lebedev V.I., Kaminsky Yu.D., Samdanchap T.H. (1998) [New processes of extraction of valuable components from ores and technology of deep mining and technogenic raw materials of Tuva and Mongolia using non-traditional methods of ore and technogenic waste with noble and rare metals]. Sostoyanie i osvoenie prirodnykh resursov Tuvy i sopredel’nykh regionov Tsentral´noy Azii, geoekologiya prirodnoy sredy i obshchestva [State and exploration of natural resources of Tuva and adjacent regions of Central Asia, geoecology of natural environment and society]. Kyzyl, TuvIENR SB RAS Publ., 14-20. (in Russian).
9. Nikolaeva L.A., Yablokova S.V. (2007) [Typomorphic features of native gold and their implication for geological prospecting]. Rudy i Metally [Ores and Metals], 6, 41-57 (in Russian)
10. Pal’yanova G.A., Kokh KA., Seryotkin Y. (2012). Formation of gold-silver sulfdes and native gold in Fe-Ag-Au-S system. Russian Geology and Geophysics, 4, 347-355.
11. Petrovskaya N.V. (1973) [Native gold]. Moscow, Nauka, 348 p. (in Russian)
12. Redder E. (1978) [Fluid inclusions in minerals]. Moscow, Mir, V. 1. 360 p. (in Russian).
13. Spiridonov E.M. (1991) [Primary Hg-bearing gold of northern Kazakhstan]. Novye dannye o mineralakh [New data on minerals], 37, 108-127. (in Russian)
14. Spiridonov E.M. (2010) [Review of gold mineralogy in main types of Au mineralization]. Zoloto Kol’skogo poluostrova i sopredel’nykh regionov: Trudy Vserossiyskoy nauchnoj konferentsii, posvyashchyonnoj 80-letiyu Kol’skogo NC RAN [Gold of the Kola Peninsula and adjacent regions. Proceedings of the Russian conference dedicated to the 80th anniversary of the Kola Scientifc Center (Russian Academy of Sciences)]. Apatity, 143-171. (in Russian)