| Eruption of the Continental Flood Basalts at -259 Ma in the Emeishan Large Igneous Province, SW China： Evidence from Laser Microprobe ^40Ar/^39Ar Dating |
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| 作者姓名： | HOU Zengqian CHEN Wen and LU Jiren Institute of Geology Chinese Academy of Geological Science Beijing Institute of Mineral Resources Chinese Academy of Geological Science Beijing |
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| 作者单位： | HOU Zengqian，CHEN Wen and LU Jiren Institute of Geology，Chinese Academy of Geological Science，Beijing 100037 Institute of Mineral Resources，Chinese Academy of Geological Science，Beijing 100037 |
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| 基金项目： | This study is financially supported by a Youth Foundation from the former Ministry of Geology and Mineral Resources and an 0utstanding Youth Foundation from the National Natural Science Foundation of China （grant 40425014）. We are grateful to Prof. Lin Jianying and Dr. Li Hongyang for their help during field work. Prof. Wang Yunliang and Dr. Song Xieyan are also acknowledged for their constructive discussion. |
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| 摘 要： | A suite of continental flood basalts sampled over a vast exposure and stratigraphic thickness in the Emeishan large igneous province (LIP), SW China was investigated for laser microprobe 40Ar/39Ar dating. There are two 40Ar/39Ar age groups for these basalts, corresponding to 259-246 Ma and 177-137 Ma, respectively. A well-defined isochron gives an eruption age of huge quantities of mafic magmas at 258.9±3.4 Ma, which is identical to previous dating and paleontological data. Much younger 40Ar/39Ar ages for some basalts with low-greenschist metamorphic facies probably recorded a late thermo-tectonic event caused by collision between the Yangtze and Qiangtang continental blocks during the Mesozoic, which resulted in the reset of argon isotope system. The 40Ar/39Ar age data, we present here, combined with previous dating and paleontological data, suggest relatively short duration (about 3 Ma) of mafic volcanism, which have important implication on mantle plume genesis of the Emeishan continental flood basalts in the LIP.
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| 关 键 词： | 地质 玄武岩 火成 岩石 |
| 收稿时间： | 2005-04-18 |
| 修稿时间： | 2/9/2006 12:00:00 AM |
Eruption of the Continental Flood Basalts at -259 Ma in the Emeishan Large Igneous Province, SW China: Evidence from Laser Microprobe ~(40)Ar/~(39)Ar Dating |
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| Authors: | HOU Zengqian CHEN Wen and LU Jiren Institute of Geology Chinese Academy of Geological Science Beijing Institute of Mineral Resources Chinese Academy of Geological Science Beijing |
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| Abstract: | Abstract A suite of continental flood basalts sampled over a vast exposure and stratigraphic thickness in the Emeishan large igneous province (LIP), SW China was investigated for laser microprobe 40Ar/39Ar dating. There are two 40Ar/39Ar age groups for these basalts, corresponding to 259–246 Ma and 177–137 Ma, respectively. A well‐defined isochron gives an eruption age of huge quantities of mafic magmas at 258.9±3.4 Ma, which is identical to previous dating and paleontological data. Much younger 40Ar/39Ar ages for some basalts with low‐greenschist metamorphic facies probably recorded a late thermo‐tectonic event caused by collision between the Yangtze and Qiangtang continental blocks during the Mesozoic, which resulted in the reset of argon isotope system. The 40Ar/39Ar age data, we present here, combined with previous dating and paleontological data, suggest relatively short duration (about 3 Ma) of mafic volcanism, which have important implication on mantle plume genesis of the Emeishan continental flood basalts in the LIP. |
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| Keywords: | laser microprobe 40Ar/39Ar age continental flood basalts Emeishan large igneous province |
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