| 新疆望峰金矿成矿流体的He、Ar同位素示踪 |
| |
| 关键词:He-Ar isotopes crust-derived fluid deep circulation of atmospheric water Wangfeng gold deposit in Xinjiang |
| 基金项目:“十一五”国家科技支撑计划项目(编号: 2006BAB07B04-05);西北大学研究生创新基金项目(编号: 10YZZ23) |
|
| 摘要点击次数: 3552 |
| 全文下载次数: 4148 |
| 摘要: |
| Helium and Argon Isotopic Tracing of Ore-forming Fluid from the Wangfeng Gold Deposit in Xinjiang |
| The Wangfeng gold deposit is located in the Bingdaban ductile shear zone along the northern margin of Mid-Tianshan. Helium and Argon isotopic compositions of fluid inclusions in pyrite were analyzed to trace the source of ore-forming fluid by using an inert gas isotopic mass spectrometer after analyzing variables that may affect He-Ar original isotopic compositions of the ore-forming fluid. The analytical results indicate that 3He/4He ratio and 40Ar/36Ar ratio vary respectively from 0.00473 Ra to 0.01079 Ra and from 301 to 413, helium and argon isotopic compositions synthetically exhibit the crust-derivation of the ore-forming fluid, which was the product of the deep circulation of atmospheric water. Meanwhile, in contrast to typical crust-derived fluid, Wangfeng ore-forming fluid has higher 4He and 40Ar, resulting in lower 3He/4He and higher 40Ar/36Ar than typical He-Ar isotopic compositions of crust-derived fluid. An analysis of main country rocks and ore-forming fluid inclusions reveals that ore-hosting country rocks with high U, Th concentrations produced much more radiogenic 4He which reduced 3He/4He ratio in comparison with normal radiogenic He isotopic composition, that atmospheric water with atmosphere-derived He-Ar isotopic compositions subsided through brittle crannies and captured radiogenic He existing in country rocks, and that some radiogenic 40Ar was obtained synchronously, which reduced 3He/4He ratio preliminarily and raised 40Ar/36Ar ratio at the pre-mineralization stage. Then, ore-forming fluid boiled due to hydrothermal decompression at the ore-forming stage, which brought 3He/4He ratio down. In summary, the ore-forming fluid of the Wangfeng gold deposit was crust-derived and reformed during the process of fluid evolution. |
| YANG Meng,WANG Ju-li,WANG Jian-qi,DANG Fei-peng.2012.Helium and Argon Isotopic Tracing of Ore-forming Fluid from the Wangfeng Gold Deposit in Xinjiang[J].Acta Geoscientica Sinica,33(5):794-800. |
| 查看全文 查看/发表评论 下载PDF阅读器 |
|
|
|
|
|