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Coupled Dissolution–Precipitation Reactions of Tennantite–Tetrahedrite Minerals in the Darasun Gold Deposit (Eastern Transbaikalia, Russia)статья
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 11 марта 2020 г.
- Авторы: Lyubimtseva N.G., Bortnikov N.S., Borisovsky S.E., Vikent’eva O.V., Prokofiev V.Yu
- Журнал: Geology of Ore Deposits
- Том: 61
- Номер: 6
- Год издания: 2019
- Издательство: Maik Nauka/Interperiodica Publishing
- Местоположение издательства: Russian Federation
- Первая страница: 530
- Последняя страница: 548
- DOI: 10.1134/S1075701519060047
- Аннотация: Heterogeneous rhythmic–zonal aggregates of tennantite-IV partly or completely replacing early homogeneous Zn-tetrahedrite-I grains and euhedral (Fe–Zn)-tennantite-I crystal were found in ores of the Darasun gold deposit. The different stages of fahlore replacement were observed. This initiates at grain boundaries and is terminated by a complete transformation into pseudomorphic, newly formed (Zn–Fe)- tennantite-IV aggregates surrounded by Zn-tetrahedrite-IV. These aggregates closely associate with bournonite and galena, and their precipitation initiated the formation of pseudomorphs. As is evident from the results of EMPA, (Fe–Zn)-tetrahedrite enriched in As in relation to Zn-tetrahedrite-I was precipitated at the initial stage. Tennantite with wide variations in the Sb/(Sb + As) and Fe/(Fe + Zn) ratios predominates in zonal heterogenous aggregates. There is a negative correlation between Sb/(Sb + As) and Fe/(Fe + Zn) ratios in (Fe–Zn)-tetrahedrite–tennantite-IV. In all sites, there is a miscibility gap between As and Sb and a sharp decrease in Sb/(Sb + As) ratio and increase in Fe/(Fe + Zn) ratio at the contact between Zn-tetrahedrite-I and newly formed (Fe–Zn)-tetrahedrite–tennantite-IV. The sharp zigzag boundaries between Zn-tetrahedrite- I and tennantite-IV and pores in newly formed aggregates provide evidence for coupled dissolution–precipitation reactions. The dissolution was initiated by disequilibrium between Zn-tetrahedrite-I and undersaturated fluid due to the precipitation of galena and bournonite. The precipitation of tetrahedrite–tennantite-IV occurred under the conditions of oscillation in Sb/(Sb + As) and Fe/(Fe + Zn) ratios due to the gradient of concentrations in the fluid. The temperature of crystallization of zonal heterogenous tennantite-IV aggregates ((134–161) ± 20°С) was calculated by the sphalerite–fahlore geothermometer. Instability of early Zn-tetrahedrite-I results from hydrothermal fluid cooling, decrease in fluid salinity, and change in the tetrahedrite and tennantite solubility due to the evolution of the conditions of semimetal migration.
- Добавил в систему: Прокофьев Всеволод Юрьевич