Mantle-derived noble gases in ore-forming fluids of the granite-related Yaogangxian tungsten deposit, Southeastern China

• Published in: Mineralium deposita 2012-08, Vol.47 (6), p.623-632
• Main Authors: Hu, Rui-Zhong, Bi, Xian-Wu, Jiang, Guo-Hao, Chen, Hong-Wei, Peng, Jian-Tang, Qi, You-Qiang, Wu, Li-Yan, Wei, Wen-Feng
• Format: Article
• Language: English
• Subjects: Earth and Environmental Science; Earth Sciences; Gases; Geochemistry; Geology; Granite; Isotopes; Low temperature; Magma; Mesozoic; Metals; Mineral Resources; Mineralogy; Pyrite; Tungsten; Veins (geology)
• ISSN: 0026-4598; 1432-1866
• DOI: 10.1007/s00126-011-0396-x

More than 90% of the tungsten resources of China are in the Nanling region of South China, and the Yaogangxian vein deposit is the largest tungsten deposit in this region. The tungsten deposits have ages of 150–160 Ma, and are spatially, temporally and genetically related to granites which were previously believed to be produced by crustal anatexis. This paper provides He and Ar isotope data of fluid inclusions in pyrite and arsenopyrite from the Yaogangxian W veins. 3 He/ 4 He ratios range from 0.41 to 3.03 Ra (where Ra is the 3 He/ 4 He ratio of air = 1.39 × 10 −6 ), and 40 Ar/ 36 Ar ratios from 328 to 1,191. Moreover, there are excellent correlations between He and Ar isotopic compositions. The results suggest that the ore-forming fluids are a mixture between a crustal fluid containing atmospheric Ar and crustal 4 He and a fluid containing mantle components. It is likely that the former is a low temperature meteoric fluid, and the later is a fluid exsolved from the W-associated granitic magma, which formed by crustal melting induced by intrusion of a mantle-derived magma.