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Gold in Pyrite: a Thermodynamic Model of Co-crystallization in Chloride Fluidsстатья
- Авторы: Prokofiev V.Yu, Akinfiev N.N., Bortnikov N.S.
- Журнал: Geology of Ore Deposits
- Том: 66
- Номер: 6
- Год издания: 2024
- Издательство: Maik Nauka/Interperiodica Publishing
- Местоположение издательства: Russian Federation
- Первая страница: 716
- Последняя страница: 727
- DOI: 10.1134/S1075701524600555
- Аннотация: Abstract—A thermodynamic description of gold-bearing pyrite as a substitution solid solution is proposed depending on external conditions and gold content in the f luid. The model is based onexperimental data of the synthetic pyrite grown in hydrothermal chloride solutions in the presence of metallic gold. The proposed model makes it possible to estimate the upper limit of gold content in pyrite. The thermodynamic model of gold-bearing pyrite was verified by modeling the process of formation of mineral associations of gold ores of the Darasun and Talatui deposits by chloride aqueous f luids in an integrated f luid-magmatic system of the Darasun ore field. Previously it was revealed that the average gold content in pyrite from the Darasun and Talatui deposits, intergrown with native gold, does not exceed 1 ppm, while synthetic pyrite grown in equi- librium with metallic gold under similar conditions contains 10–150 ppm of gold. This contradiction does not allow explaining the formation of gold ores of the Darasun ore field by its direct crystallization from hydrothermal fluid. A possible explanation is the presence of an additional stage of ore transformation, in which recrystallization of sulfides occurred with gold undersaturated solutions. It was shown that a decrease in gold concentration in the mineral-forming f luid below the saturation limit should lead to a synchronous decrease in the gold concentration in the resulting pyrite. The calculated values of gold concentration in model pyrite make it possible to estimate gold concentrations in mineral-forming chloride f luids at different stages of the rature. It has been shown that natural gold-bearing pyrite from various gold deposits was formed mainly from chloride f luids undersaturated to gold.
- Добавил в систему: Прокофьев Всеволод Юрьевич