Academic Journal
Mineral Assemblages and Ore-Forming Physicochemical Conditions of the La’erma and Qiongmo Au–Se Deposits in the Western Qinling Orogen, Central China
| العنوان: | Mineral Assemblages and Ore-Forming Physicochemical Conditions of the La’erma and Qiongmo Au–Se Deposits in the Western Qinling Orogen, Central China |
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| المؤلفون: | Jiajun Liu, Guoming Weng, Emmanuel John M. Carranza, Degao Zhai, Yinhong Wang, Fangfang Zhang, Shen Gao, Lei Xu |
| المصدر: | Minerals, Vol 14, Iss 5, p 507 (2024) |
| بيانات النشر: | MDPI AG |
| سنة النشر: | 2024 |
| المجموعة: | Directory of Open Access Journals: DOAJ Articles |
| مصطلحات موضوعية: | La’erma and Qiongmo deposits, Au–Se mineral associations, physicochemical conditions, high ∑Se/S, water–rock reactions, Mineralogy, QE351-399.2 |
| الوصف: | The La’erma and Qiongmo Au–Se deposits are characterized by a paragenetic Au–Se association hosted in the siliceous formation of the Cambrian Taiyangding Group in the western Qinling Orogen, central China. The La’erma and Qiongmo Au–Se deposits, which are considered to be the Carlin gold deposits, comprise a variety of selenides, native gold, and stibnite coexisting with baryte. Four stages have been recognized: sage I comprises pyrite and quartz with minor stibnite; stage II is composed mainly of sulfides; stage III is composed mainly of selenides; and stage IV is dominated by quartz–baryte–dickite. Stages II and III are the main metallogenic stages. Based on changes in mineral assemblages, combined with fluid inclusions and thermodynamic data, we evaluated the physicochemical conditions of the main metallogenic stages. The log f S 2 values of ore-forming fluids at stage II ranged between −10.44 and −14.60 with log f Se 2 being less than −10.70. Comparably, during stage III, which is characterized by numerous selenides, the log f S 2 and log f Se 2 ranged from −7.13 to −12.20 and −13.98 to −8.82, respectively. The occurrence of baryte during the mineralization suggests a consistently oxidizing condition, which can effectively remove Au from fluids. More importantly, this study emphasizes that the oxidizing condition was only a fundamental prerequisite for the deposition of selenides, and a high ∑Se/S ratio of the fluid ultimately controlled the precipitation of selenides. In the La’erma and Qiongmo deposits, intense water–rock reactions occurred as ore-forming fluids flowed into the Se-rich siliceous formations, resulting in an increase in the ∑Se/S ratio of the fluid and in the precipitation of selenides. |
| نوع الوثيقة: | article in journal/newspaper |
| اللغة: | English |
| تدمد: | 2075-163X |
| Relation: | https://www.mdpi.com/2075-163X/14/5/507; https://doaj.org/toc/2075-163X; https://doaj.org/article/76880502f82a41eaba600172b5b1dea0 |
| DOI: | 10.3390/min14050507 |
| الاتاحة: | https://doi.org/10.3390/min14050507 https://doaj.org/article/76880502f82a41eaba600172b5b1dea0 |
| رقم الانضمام: | edsbas.4B7BF9E1 |
| قاعدة البيانات: | BASE |
Full Text Finder | تدمد: | 2075163X |
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| DOI: | 10.3390/min14050507 |