| 冈底斯成矿带东段矿床成矿系列及找矿突破的关键问题研究 |
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| 关键词:minerogenetic series of ore deposits porphyry-type skarn-type Gangdise metallogenic belt Tibet |
| 基金项目:由国家自然科学基金项目(编号: 41172077)；国家973项目(编号: 2011CB403103)；青藏专项(编号: 1212011085529)；地质大调查项目“全国重要矿产和区域成矿规律研究”(编号: 1212010733803)；西藏天圆矿业资源开发有限公司项目（编号: 2006G-07）；中国黄金集团项目(编号: E0804) |
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| Minerogenetic Series of Ore Deposits in the East Part of the Gangdise Metallogenic Belt |
| The Gangdese metallogenic belt is one of the most important continual basements for mineral resources in China. The Lhasa Terrane (Gangdise magmatic arc, III43) is one of the most significant third-level (III) metallogenic belts. There is a region from Lhaze County to Gongbo’gyamda County which is 600 km long and 90 km wide and has been studied in detail. There are five ore concentrated areas with the superlarge size Cu polymetallic deposits based on exploration and evaluation: Xiongcun Cu-Au ore concentrated area, Tinggong-Chongjiang Cu polymetallic ore concentrated area, Jiama-Qulong-Bangpu Cu polymetallic ore concentrated area, Mengyaa-Dongzhongla-Yaguila polymetallic ore concentrated area, and Chengba-Nuri W-Mo-Cu ore concentrated area. The research in recent years shows that there are five groups of minerogenetic series composed of Pb-Zn-Ag minerogenetic series group related to Hercynian volcanism and rift valley, Cu-Au-Fe-Pb-Zn-Ag-Mo minerogenetic series group related to Indo-Chinese and Yanshanian sedimentation-tectonic magmatism, Cu-Au-Fe-Pb-Zn-Ag-Mo-W-U-salt deposits minerogenetic series group related to Himalayan tectonic magmatism and sedimentation in the Gangdise metallogenic belt, which are composed of six minerogenetic series and ten subseries of ore deposits. The major subserieses include Cu-Au-Ag-Pb-Zn subseries related to Early Jurassic-Late Jurassic arc-type intermediate-felsic volcanic-supergene rock formation between 173 Ma and 160 Ma in the Yaba Formation in the periphery of Xiongcun and east of Lhasa with a promising potential; Pb-Zn-Ag-Mo-W-Fe subseries (Sharang style, Yaguila style and Dongzhongla style) related to Paleocene-Eocene intermediate-felsic volcanic rock and intermediate-supergene rock formation between 65 Ma and 38 Ma in the Linzhou Basin-Nanmulin Basin and Longger dislocated upwarping belt in the north with a promising potential; Cu-Mo-Pb-Zn-W-Au-Ag subseries (Qulong style, Jiama style, Chongjiang-Tinggong style, Zhunuo style and Bangpu style) related to Miocene intermediate-felsic supergene rock formation between 17 Ma and 13 Ma in the central zone of the east Gangdise metallogenic belt with a promising potential, especially the skarn-type Cu polymetallic deposits in the contact zone of ore-bearing porphyry. The distribution of metals from south to north are Cu-Au (porphyry type)→Mo-W(Cu) (porphyry-skarn type)→Cu-Mo-Pb-Zn (Au-Ag) (porphyry-skarn type)→Mo (Cu) (porphyry type)→Pb-Zn-Mo-W-Fe (porphyry-skarn type) →Pb-Zn (Ag) (hydrothermal vein type). The metallogenic ages from south to north are 173–154 Ma (Xiongcun)→40–20 Ma(Chongmuda etc.)→17–13 Ma (Qulong, Jiama etc.)→65–38 Ma (Sharang, Yaguila etc.). Biotite granite (granite porphyry, quartz porphyry) magmatic activities of Late Yanshanian and Late Himalayanian periods in Gangdise controls the distribution of skarn type Cu-Pb-Zn-Fe-Mo ore deposits. Most skarn type ore deposits occur in the intrusion or the surrounding area within 0-4 km from the intrusion with Cu, Mo, W mineralizations. There are Mo-W-Cu- Zn-Pb-Ag-Au ore bodies occurring in the interlaminar structure between limestone and black rocks in the external contact zone. The major host rock assemble is limestone (marble) + black slate, tuff, sand-slate. The ore-bearing strata include Late Cretaceous-Early Permian Angjie Formation and Laigu Formation, Permian Luobadui Formation and Xiala Formation, and interlaminar structure between Middle Jurassic Duodigou Formation and Late Jurassic Linbuzong Formation. There are five major types of ore deposits, i.e., the skarn type polymetallic deposit close to porphyry Mo (Cu) deposit of Late Yanshanian-Early Himalayanian periods (126–40 Ma) in Nyainqentanglha region and four major promising areas such as the Yeba Formation (J2y) in the east of Lhasa based on the “vacancy” theory. Some significant opinions are proposed such as the exploration breakthrough for orogenic Au deposits in the accretionary wedge and the model of the overthrust-slide nappe structure controlling the magmatism and mineralization. |
| TANG Ju-xing,Dorji,LIU Hong-fei,LANG Xing-hai,ZHANG Jin-shu,ZHENG Wen-bao,YING Li-juan.2012.Minerogenetic Series of Ore Deposits in the East Part of the Gangdise Metallogenic Belt[J].Acta Geoscientica Sinica,33(4):393-410. |
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