Fluid inclusions of the Qibaoshan Cu-Au deposit, Shandong Province, China
文献类型：期刊论文
| 作者 | Xu WenGang1; Fan HongRui1; Hu FangFang1; Wang Yong1,2; Yang KuiFeng1 |
| 刊名 | ACTA PETROLOGICA SINICA
 |
| 出版日期 | 2015-04-01 |
| 卷号 | 31期号:4页码:1015-1030 |
| 关键词 | Epithermal Porphyry Fluid inclusion Vapour contraction Fluid mixing Gold precipitation Qibaoshan Cu-Au deposit Shandong Province |
| 文献子类 | Article |
| 英文摘要 | The Qibaoshan deposit is a large Cu-Au deposit located in southwest of Shandong Province, China. Three types of fluid inclusions are recognized in recrystallized quartz phenocrysts of the deep located altered porphyry: Type 1, halite-bearing inclusions; Type 2, pure vapor inclusions; and Type 3, vapor-rich inclusions. They commonly show coexistence in samples. Two types of fluid inclusions in quartz veins with different ore minerals representing different hydrothermal stages, and in quartz crystal column collected from the shallow open pit are identified in this study: Type 4, liquid-rich inclusions with vapour volume fraction of 5% similar to 8%; Type 5, aqueous inclusions with vapour volume fraction of 10% similar to 20%, which can be subdivided into 5a and 5b according to their differential occurrences. Microthermometric analyses indicate that Type 1 inclusions homogenized via halite dissolution at temperatures of 375 to 450 degrees C with calculated salinities of 43. 8% to 52. 2% NaCleqv; Type 3 inclusions displayed a critical homogenization mode based on the comparison between homogenization pressures and critical pressures at the same homogenization temperatures (347 to 420 degrees C) with calculated salinities of 0. 8% to 7. 1% NaCleqv; Type 4, 5a and 5b inclusions homogenized to liquid phase at temperatures of 221 to 327 degrees C, 199 to 379 degrees C and 109 to 193 degrees C, respectively, with calculated salinities of 2.4% to 7. 8% NaCleqv, 10. 2% to 16. 8% NaCleqv, and 0. 3% to 4. 0% NaCleqv, respectively. Type 2 inclusions were not analyzed in this study due to high vapor volume fraction (> 80%), which makes observation of homogenization behaviors difficult. The coexistence of Type 1, 2 and 3 inclusions is not caused by fluid immiscibility, because the homogenization pressures (Ph) of Type 1 inclusions (Ph = 623. 46 to 1111. 81 bar) are much higher than those of Type 3 inclusions (Ph = 139. 18 to 362. 47bar). According to previous experimental researches, fluids represented by Type 2 and 3 inclusions are believed to be directly exsolved from the melts in early crystallization stage at low to intermediate pressure, which hosted abundant gold bisulfides, while the brine represented by Type 1 inclusions exsolved later at high pressure caused by crystallization and system resealing following brecciation, which enriched the Fe-chlorine complex. A mixing process is proposed in this study to interpret the coexisting phases. According to the H-O-S isotopic studies hydrothermal fluids represented by Type 4 and 5a inclusions in epithermal system are of magmatic origin, which would be mixed by meteoric water in late stage generating a low salinity fluids represented by Type 5b inclusions. Based on the fact that, both Type 3 and 4 inclusions fluids are magmatic origin, sharing a same salinity range (5% similar to 7% NaCleqv), and display a gradually increasing density from 0. 4101 to 0. 8816g/cm(3) with temperature decreases from ca. 450 degrees C to ca. 250 degrees C, we suppose that Type 4 inclusions-representing fluid is produced by contraction of Type 3 inclusions-representing fluids at elevated pressures, reflecting the hydrothermal transition from porphyry to epithermal system. The vapour contracting liquid fluids have physical ability to mix with any other aqueous ones including the brine represented by Type 1 inclusions in cryptoexplosion structure, which can consequently consume the HS- in brine causing the gold precipitation, and form the epithermal mineralization in this district. |
| WOS关键词 | HYDROTHERMAL ORE-DEPOSITS ; PAPUA-NEW-GUINEA ; PORPHYRY COPPER-DEPOSITS ; AQUEOUS FLUIDS ; SILICATE MELTS ; EPITHERMAL TRANSITION ; ISOTOPE GEOCHEMISTRY ; GOLD MINERALIZATION ; MOLYBDENUM DEPOSIT ; CHEMICAL EVOLUTION |
| WOS研究方向 | Geology |
| 语种 | 英语 |
| WOS记录号 | WOS:000353869400010 |
| 源URL | [http://ir.iggcas.ac.cn/handle/132A11/62607]  |
| 专题 | 地质与地球物理研究所_中国科学院矿产资源研究重点实验室 |
| 作者单位 | 1.Chinese Acad Sci, Inst Geol & Geophys, Key Lab Mineral Resources, Beijing 100029, Peoples R China 2.Chinese Acad Geol Sci, Inst Geomech, Beijing 100081, Peoples R China |
| 推荐引用方式 GB/T 7714 | Xu WenGang,Fan HongRui,Hu FangFang,et al. Fluid inclusions of the Qibaoshan Cu-Au deposit, Shandong Province, China[J]. ACTA PETROLOGICA SINICA,2015,31(4):1015-1030. |
| APA | Xu WenGang,Fan HongRui,Hu FangFang,Wang Yong,&Yang KuiFeng.(2015).Fluid inclusions of the Qibaoshan Cu-Au deposit, Shandong Province, China.ACTA PETROLOGICA SINICA,31(4),1015-1030. |
| MLA | Xu WenGang,et al."Fluid inclusions of the Qibaoshan Cu-Au deposit, Shandong Province, China".ACTA PETROLOGICA SINICA 31.4(2015):1015-1030. |
入库方式： OAI收割
来源：地质与地球物理研究所
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