| Helium and argon isotope geochemistry of alkaline intrusion-associated gold and copper deposits along the Red River–Jinshajiang fault belt, SW China | |
Rui-Zhong Hu ; P.G. Burnard; Xian-Wu Bi; Mei-Fu Zhou; Jian-Tang Pen; Wen-Chao Su; Kai-Xing Wu
| |
| 2004 | |
| Source Publication | Chemical Geology
 |
| Volume | 203Issue:3-4Pages:305-317 |
| metadata_24 | 其它 |
| Other Abstract | The Red River–Jinshajiang strike-slip fault zone on the eastern margin of the Tibetan plateau was originally produced by the India–Eurasia collision f60–70 Myr ago. Numerous post-collisional, mantle-derived alkaline igneous rocks, with ages of f40–30 Ma, have been intruded along this fault zone. In recent years, several copper and gold deposits associated with the alkaline intrusions of this region were discovered, such as the Yao’an and Beiya gold deposits and the Yulong and Machangqing copper deposits studied in this paper. The mineralised intrusions are felsic, with SiO2 ranging from 61.4 to 67.7 wt.%,K2O+Na2O from 8.1 to 11.5 wt.% and K2O/Na2O>1. The deposits are located at both the exo- and endo-contact zones of the intrusions. The mineral deposits are of hydrothermal origin, with the ore-forming temperatures mainly in the range 150–450 jC. This paper presents He and Ar isotope analyses of these four deposits. The concentrations of 4He trapped in fluid inclusions of pyrites from the ores are (0.7–54.1) 10 6 cm3 STP g 1, and those of 40Ar are (0.6–7.3) 10 6 cm3 STP g 1, 3He/4He ratios are 0.3–2.5 Ra (Ra represents the 3He/4He ratio of air, 1.39 10 6), 40Ar/36Ar ratios are 316–1736,and 3He/36Ar ratios are 0.2–11.2 10 3. Generally, the 3He/4He, 40Ar/36Ar and 3He/36Ar ratios for the gold deposits are higher than those for the copper deposits. We suggest that the ore-forming fluids of both gold and copper deposits were differentiated from the mantle-derived alkaline magmas, but were diluted by modified air-saturated water (MASW) that experienced intensive interaction with crustal rocks.However, the magmatic fluids responsible for the gold deposits were less extensively diluted by MASW, resulting in higher 3He/4He, 40Ar/36Ar and 3He/36Ar ratios than the copper deposits. |
| Keyword | Red River–jinshajiang Alkaline Intrusion Copper And Gold Deposits Helium And Argon Isotopes Ore-forming Fluid Mantle Fluids |
| Subject Area | 中国典型特殊区带大规模成矿作用及其动力学 |
| Indexed By | SCI |
| Language | 英语 |
| Document Type | 期刊论文 |
| Identifier | http://ir.gyig.ac.cn/handle/352002/3076 |
| Collection | 矿床地球化学国家重点实验室_矿床地球化学国家重点实验室_期刊论文 矿床地球化学国家重点实验室 |
| Recommended Citation GB/T 7714 | Rui-Zhong Hu,P.G. Burnard,Xian-Wu Bi,等. Helium and argon isotope geochemistry of alkaline intrusion-associated gold and copper deposits along the Red River–Jinshajiang fault belt, SW China[J]. Chemical Geology,2004,203(3-4):305-317. |
| APA | Rui-Zhong Hu.,P.G. Burnard.,Xian-Wu Bi.,Mei-Fu Zhou.,Jian-Tang Pen.,...&Kai-Xing Wu.(2004).Helium and argon isotope geochemistry of alkaline intrusion-associated gold and copper deposits along the Red River–Jinshajiang fault belt, SW China.Chemical Geology,203(3-4),305-317. |
| MLA | Rui-Zhong Hu,et al."Helium and argon isotope geochemistry of alkaline intrusion-associated gold and copper deposits along the Red River–Jinshajiang fault belt, SW China".Chemical Geology 203.3-4(2004):305-317. |
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