Вид документа : Статья из журнала Шифр издания : 54/T 44 Автор(ы) : Kovalenker V. A., Safonov Yu. G., Naumov V. B., Rusinov V. L. Заглавие : The epithermal gold-telluride Kochbulak deposit (Uzbekistan) Место публикации : Geology of Ore Deposits. - 1997. - Vol. 39, № 2. - С. 107-128 Примечания : Bibliogr. : p. 128 (42 ref.) ББК : 54 Предметные рубрики: ХИМИЧЕСКИЕ НАУКИ Аннотация: The Paleozoic epithermal gold-telluride Kochbulak deposit is situated on the northern slope of the Kurama Range in the central Tien Shan (Uzbekistan). The deposit is located within an andesite-dacite volcanic sequence (C2-3) intruded by subalkaline granodiorite and granosyenite porphyry dikes (C3-P1). The ore-forming system of the deposit originated and evolved during the orogenic uplift associated with aerial volcanism and emplacement of porphyritic granitoids. The Kochbulak deposit contains a great diversity of ore-forming sulfides, sulphosalts, tellurides, and selenides, several of which were first found there. The deposit has features of epithermal mineralization of both the adularia-sericite and acid-sulfate genetic types and mesothermal gold mineralization. The deposit consists of high- and low-angle veins and ore-bearing breccia pipes. The pipe-shaped bodies and veins differ in ore, gangue, and metasomatic mineral assemblages. The ore bodies hosted by explosive-hydrothermal breccias contain goldfieldite, famatinite, luzonite, enargite, diaspore, and pyrophyllite and, therefore, have pronounced features of epithermal mineralization of the acid-sulfate type. The ore veins show evidence of deeper formation and are associated with quartz-carbonate-sericite wall rock alteration. Our study of mineral assemblages, fluid inclusions, sulfur, oxygen, and hydrogen isotopes, and thermodynamic calculations show that the Kochbulak deposit was formed during a cyclic multistage process with periodic alternation of sealing along with tectonic and explosive opening of the fluid channel ways. The ore-forming process is subdivided into the preore, I to III ore, and postore stages related to fracture opening. Three types of solutions took part in the formation of gold-sulfide-sulphosalt-telluride mineralization. They were distinct in temperature, composition, salinity, and proportion of meteoric and magmatic water and other volatile components. The temperature generally decreased from 465°C to 100°C, and slightly increased at the beginning of each stage of the ore-forming process. Pressure, salinity, ion and gas composition of solutions, and the oxygen isotope composition of water varied as well. The deposition of gold-productive mineral assemblages was caused by changes in pH, Eh, activities of S2, O2, and Te2. The recurrence of these changes and repeated mineral deposition within the same depth intervals formed bodies very rich in ore components. The above-mentioned data suggest the Kochbulak deposit represents a particular type of gold-telluride mineralization, which originated within a wide range of physicochemical conditions at hypabyssal to subsurface depths.???? Держатели документа: Центральная научная библиотека УрО РАН Доп.точки доступа: Kovalenker, V. A.; Safonov, Yu. G.; Naumov, V. B.; Rusinov, V. L.