| Geochronology of the Gabbro–mafic Microgranular Enclaves–granite Associations in the Gejiu District, Yunnan Province and Their Geodynamic Significance |
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| 作者姓名： | CHENG Yanbo and MAO Jingwen |
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| 作者单位： | 1 Faculty of the Earth Sciences and Resources, China University of Geosciences, Beijing 100083
2 School of Earth and Environmental Sciences, James Cook University, Townsville, 4811, Australia
3 MLR Key Laboratory of Metallogeny and Mineral Assessment, Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing, 100037 |
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| 基金项目： | We appreciate the assistance of Mr Hou Kejun with zircon U–Pb dating, Dr Zhenyu Chen with zircon CL imaging. We also want to express our thanks to Mr. Guopei Mo, Mr. Xiang Tong, Mr. Junde Wu and other local geo-workers from Yunnan Tin Group for their assistance during our field works. This study was supported by the National Science Foundation of China (40930419), Special Research Funding for the Public Benefits Sponsored by MLR (200911007–12), Research Program of Yunnan Tin Group (2010–04A), Geological Investigation Program by CGS (1212011120994), and the Fundamental Research Funds for the Central Universities (2–9–2010–21). |
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| 摘 要： | Many igneous rocks distribute in Gejiu tin polymetallic ore-field at Yunnan province, rocks including basalt, gabbro, mafic microgranular enclaves, granites (porphyritic granite and equigranular granite) and akaline rocks. The ages of the granites and akaline rocks which are considered to have genetic connecting with the mineralization have been comfirmed, but the gabbro-mafic microgranular enclaves-granite assemblage’s ages are still unknown. By means of LA-ICP-MS zircon U-Pb dating, the data of Shenxianshui equigranular granite, the mafic microgranular enclave in Jiasha area, the host rock of the mafic microgranular enclaves and the Jiasha gabbro are around ~80 Ma. Besides the above mentioned data, a group of new ages at ~30 Ma were discovered in this study, which is from gabbro and mafic microgranular enclaves. Based on the previous data and the new data gained this time, we suggest the major geochronology framework of the magmatism and mineralization events in Gejiu area is ~80 Ma, which is consistent with the Late Cretaceous magmatism and mineralization events in the whole southeast Yunnan and west Guangxi area and they were suggested to belong to the same geotectonic setting in late Yenshannian. And the new ages of the ~30 Ma obtained in this study is considered to represent a responding to the complicate tectonic evolution history of the Tibetan orogenic events in Cenozoic.
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| 关 键 词： | gabbro granite mafic microgranular enclaves geochronology geodynamic setting Gejiu |
| 收稿时间： | 2011/9/10 0:00:00 |
| 修稿时间： | 2011/10/12 0:00:00 |
Geochronology of the Gabbro–mafic Microgranular Enclaves–granite Associations in the Gejiu District,Yunnan Province and Their Geodynamic Significance |
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| Authors: | CHENG Yanbo MAO Jingwen |
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| Institution: | 1. Faculty of the Earth Sciences and Resources, China University of Geosciences, Beijing 100083;2. School of Earth and Environmental Sciences, James Cook University, Townsville, 4811, Australia;3. MLR Key Laboratory of Metallogeny and Mineral Assessment, Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing, 100037 |
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| Abstract: | Many igneous rocks distribute in Gejiu tin polymetallic ore‐field at Yunnan province, rocks including basalt, gabbro, mafic microgranular enclaves, granites (porphyritic granite and equigranular granite) and akaline rocks. The ages of the granites and akaline rocks which are considered to have genetic connecting with the mineralization have been comfirmed, but the gabbro‐mafic microgranular enclaves‐granite assemblage's ages are still unknown. By means of LA‐ICP‐MS zircon U‐Pb dating, the data of Shenxianshui equigranular granite, the mafic microgranular enclave in Jiasha area, the host rock of the mafic microgranular enclaves and the Jiasha gabbro are around ～80 Ma. Besides the above mentioned data, a group of new ages at ～30 Ma were discovered in this study, which is from gabbro and mafic microgranular enclaves. Based on the previous data and the new data gained this time, we suggest the major geochronology framework of the magmatism and mineralization events in Gejiu area is ～80 Ma, which is consistent with the Late Cretaceous magmatism and mineralization events in the whole southeast Yunnan and west Guangxi area and they were suggested to belong to the same geotectonic setting in late Yenshannian. And the new ages of the ～30 Ma obtained in this study is considered to represent a responding to the complicate tectonic evolution history of the Tibetan orogenic events in Cenozoic. |
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| Keywords: | gabbro granite mafic microgranular enclaves geochronology geodynamic setting Gejiu |
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