| 西藏铁格隆南超大型浅成低温热液铜(金、银)矿床的形成时代及其地质意义 |
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| 关键词:porphyry type epithermal type isotope chronology Bangonghu–Nujiang metallogenic belt South Tiegelong Tibet |
| 基金项目:国家“973”项目(编号: 2011CB403103);青藏专项(编号: 1212010818089);中铝资源西藏金龙矿业股份有限公司项目(编号: XZJL-2013-JS03) |
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| Formation Epoch of the South Tiegelong Supelarge Epithermal Cu (Au-Ag) Deposit in Tibet and Its Geological Implications |
| The South Tiegelong (Rongna) deposit, the first superlarge epithermal porphyry Cu (Au, Ag) deposit discovered in Tibet, is situated in the Duolong ore district along the west segment of the Bangong Co–Nujiang River metallogenic belt of Tibet. Both the exploration work and the scientific study of this deposit are being carried out at present. In combination with scientific geological logging, the authors applied the zircon U-Pb and molybdenite Re-Os isotopic dating to the newly found mineral-bearing quartz diorite porphyry and molybdenite. The LA-ICP- MS zircon U-Pb dating of the porphyry yielded a petrogenic age of (120.2±1.0) Ma, and the Re-Os isotopic model ages of molybdenite are distributed in the range of 117.8~119.4 Ma, which vary limitedly with an average model age of (118.45±0.76) Ma. The Re-Os isochron age is (119.0±1.4) Ma (MSWD=0.34). The petrogenic age and the metallogenic age are very close to each other, with the metallogenic age slightly later than the petrogenic age, which indicates that the rock-forming process and the ore-forming process belonged to the same porphyry-epithermal metallogenic system. The values of 187Re, ranging from 230.47 to 1226.6 (μg/g), imply that ore-forming materials were derived from the mantle and the aggregation of the massive metal materials was probably related to the magmatism which happened along the boundary between the mantle and the crust. A comparative study reveals that the mineralization of the South Tiegelong deposit was controlled by the same tectonomagmatic metallogenic system as that of the Duobuza and Bolong porphyry copper-gold deposit. The formation of this system was undoubtedly related to the northward subduction of the Bangonghu–Nujiang Ocean Basin in Early Cretaceous. |
| FANG Xiang,TANG Ju-xing,SONG Yang,YANG Chao,DING Shuai,WANG Yi-yun,WANG Qin,SUN Xing-guo,LI Yu-bin,WEI Lu-jie,ZHANG Zhi,YANG Huan-huan,GAO Ke,TANG Pan.2015.Formation Epoch of the South Tiegelong Supelarge Epithermal Cu (Au-Ag) Deposit in Tibet and Its Geological Implications[J].Acta Geoscientica Sinica,36(2):168-176. |
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