| 滇西无量山群北段变质基性火山岩夹层年龄及其地质意义 |
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| 关键词:Lancangjiang area of western Yunnan Wuliangshan Group metamorphic basic volcanic rock LA-ICP-MS zircon U-Pb Paleo-Tethys Ocean |
| 基金项目:中国地质调查局地质调查项目(编号: DD20179247) |
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| LA-ICP-MS Zircon U-Pb Age of Metamorphic Basic Volcanic Rocks in the Northern Segment of the Wuliangshan Group, Western Yunnan Province,and Its Geological Significance |
| Wuliangshan Group, which was named by Xiaguan Geological Survey in 1975, is composed of epimetamorphic sandstone and mudstone representing a set of littoral facies-shallow sea shelf facies sediments. Its formation age has been generally considered to be Paleozoic, which, however, is not based on the evidence of fossils or accurate dating. In this study, the authors identified the stratigraphic sequence composed of two layers of metamorphic basic volcanic rock in the lower and upper member of Wuliangshan Group (PzW4) in Maocaopin village, Yunlong county. It is held that its original rock was basalt formed in an ocean spread environment, according to comprehensive analysis of the rock occurrence in the field, the thin section and rock geochemistry. The selected magmatic zircons 206Pb/238U isotopic ages of the lower and upper parts of the metamorphic basic volcanic rocks, measured by LA-ICP-MS, were (327±11) Ma and (284±3.7) Ma respectively, corresponding to the Late Early Carboniferous and Late Early Permian. These data provide an important chronological constraint for the formation and evolution of Wuliangshan Group. This achievement is very important for the further study of the tectonic characteristics and evolution history of the Paleo-Tethys Ocean in Late Paleozoic. |
| WU Ji-wen,LIN Yu,LÜ Yong,LIAO Jia-fei,WU Liang-jun,MENG Qing-xin.2019.LA-ICP-MS Zircon U-Pb Age of Metamorphic Basic Volcanic Rocks in the Northern Segment of the Wuliangshan Group, Western Yunnan Province,and Its Geological Significance[J].Acta Geoscientica Sinica,40(6):871-883. |
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