| Geochronology and Geochemistry of Metallogenetic Porphyry Bodies from the Nongping Au-Cu Deposit in the Eastern Yanbian Area, NE China: Implications for Metallogenic Environment |
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| 作者姓名： | REN Yunsheng JU Nan ZHAO Hualei WANG Hui HOU Kejun and LIU Shen |
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| 作者单位： | 1 College of Earth Sciences, Jilin University, Changchun 130061, China
2 MRL Key Laboratory of Metallogeny and Mineral Assessment, Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China
3 State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China |
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| 基金项目： | These research results are parts of projects financially supported by the China Geological Survey (No. 1212011085485), Basic Research Foundation of Jilin University (No. 200903025 and 201004001). The authors are grateful to Li Chenhui from No.603 Team of the Bureau of Non-ferrous Geology of Jilin Province for his support in the field survey. |
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| 摘 要： | The metallogenetic porphyry bodies in the Nongping Au-Cu deposit, in the eastern Yanbian area, mainly include porphyritic granodiorite and biotite granodiorite porphyry. They are featured with high silicon and enrichment in sodium, and classified into sodic rocks of low-K tholeiitic basalt series. Except slightly low Sr content, the rock basically has the geochemical characteristics of the adakite: relatively high A12O3 content, relatively low MgO content, depletion in Y and Yb; relative enrichment in large ion lithophile elements (LILEs) and light rare-earth elements (LREEs), relatively low content of high field strength elements (HFSEs); positive Eu anomaly or weak negative Eu anomaly. In situ zircon dating technology LA-MC-ICP-MS was used to conduct single-grain zircon dating of biotite granodiorite porphyry, and the results show that the age of metallogenetic porphyry body is 100.04±0.88 Ma, indicating that the porphyry bodies were emplaced in the late Cretaceous period. According to the regional tectonic setting and the comparison with the same kind of deposits, we think that the metallogenetic porphyry bodies in the Nongping Au-Cu deposit have a close genetic connection with the subduction of the Pacific plate in the late Yanshanian period. The adakitic magma generated from partial melting of the subducting plate has high formation temperature, high oxygen fugacity, and volatile constituents’ enrichment, so it is helpful for enrichment of metallogenetic elements and plays an important role in the formation of porphyry Au-Cu deposits in this region.
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| 关 键 词： | porphyry body zircon U-Pb dating adakitic rock Nongping Au-Cu deposit |
| 收稿时间： | 2012/2/28 0:00:00 |
| 修稿时间： | 2012/3/28 0:00:00 |
Geochronology and Geochemistry of Metallogenetic Porphyry Bodies from the Nongping Au-Cu Deposit in the Eastern Yanbian Area,NE China: Implications for Metallogenic Environment |
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| Authors: | REN Yunsheng JU Nan ZHAO Hualei WANG Hui HOU Kejun and LIU Shen College of Earth Sciences Jilin University Changchun China MRL |
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| Institution: | Key Laboratory of Metallogeny and Mineral Assessment, Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China 3 State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China |
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| Abstract: | The metallogenetic porphyry bodies in the Nongping Au-Cu deposit, in the eastern Yanbian area, mainly include porphyritic granodiorite and biotite granodiorite porphyry. They are featured with high silicon and enrichment in sodium, and classified into sodic rocks of low-K tholeiitic basalt series. Except slightly low Sr content, the rock basically has the geochemical characteristics of the adakite: relatively high A12O3 content, relatively low MgO content, depletion in Y and Yb; relative enrichment in large ion lithophile elements (LILEs) and light rare-earth elements (LREEs), relatively low content of high field strength elements (HFSEs); positive Eu anomaly or weak negative Eu anomaly. In situ zircon dating technology LA-MC-ICP-MS was used to conduct single-grain zircon dating of biotite granodiorite porphyry, and the results show that the age of metallogenetic porphyry body is 100.04±0.88 Ma, indicating that the porphyry bodies were emplaced in the late Cretaceous period. According to the regional tectonic setting and the comparison with the same kind of deposits, we think that the metallogenetic porphyry bodies in the Nongping Au-Cu deposit have a close genetic connection with the subduction of the Pacific plate in the late Yanshanian period. The adakitic magma generated from partial melting of the subducting plate has high formation temperature, high oxygen fugacity, and volatile constituents’ enrichment, so it is helpful for enrichment of metallogenetic elements and plays an important role in the formation of porphyry Au-Cu deposits in this region. |
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| Keywords: | porphyry body zircon U-Pb dating adakitic rock Nongping Au-Cu deposit |
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