Генезис золото-кварцевого месторождения Чармитан (Узбекистан)статья
Статья опубликована в журнале из списка RSCI Web of Science
Статья опубликована в журнале из перечня ВАК
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 23 августа 2019 г.
Аннотация:Data on fluid inclusions and stable isotope composition, analysis of mineral assemblages, and thermodynamic calculations are used to work out a genetic model for the Charmitan gold-quartz deposit. The ores of the deposit precipitated at temperatures from 400 to 150 degrees C, under pressures of 2.77-0.9 kbar, from fluids with pH similar to 5 +/- 1. The oxygen fugacity did not exceed the values typical of a pyrite-pyrrhotite-magnetite buffer (10(-38) to 10(-29) bar), the sulfur activities were 10(-8) to 10(-20), CO2 fugacities varied from 10(2.6) to 10(1.5) and CH4 fugacities ranged from 10(1.5) to 10(2.6) bar. The minerals crystallized from fluids of various compositions: (a) H2O-rich CO2- and CH4-bearing fluid with dissolved chlorides (1.5-15 wt % equiv. NaCl), (b) vapor-rich fluid composed of CO2, CH4, and (c) aqueous-saline fluid with a salinity up to 10 wt % equiv. NaCl. The occurrence of syngenetic liquid-rich and vapor-rich inclusions is evidence of the immiscibility of the initial fluid into two fluids at the earliest productive stages. The delta(18)O, delta(13)C and delta(34)S of fluids were calculated to be +1.6 to +6.6 parts per thousand, -0.6 to -17 parts per thousand, and +2.6 to +10.7 parts per thousand, respectively. These variations suggest a mixing of fluids from different sources. According to the proposed genetic model, fluids and components of magmatic origin dominated during ore formation, but those derived from metamorphic dehydration and decarbonatization of host rocks also participated.