SHRIMP zircon U–Pb geochronological and whole-rock geochemical evidence for an early Neoproterozoic Sibaoan magmatic arc along the southeastern margin of the Yangtze Block |
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| Authors: | Mei-Fang Ye Xian-Hua Li Wu-Xian Li Ying Liu Zheng-Xiang Li |
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| Institution: | aKey Laboratory of Isotope Geochronology and Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China;bGraduate School of Chinese Academy of Sciences, Beijing 100039, China;cTectonics Special Research Centre, School of Earth and Geographic Sciences, The University of Western Australia, Crawley, WA 6009, Australia |
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| Abstract: | It has been generally accepted that the South China Block was formed through amalgamation of the Yangtze and Cathaysia Blocks during the Proterozoic Sibaoan orogenesis, but the timing and kinematics of the Sibao orogeny are still not well constrained. We report here SHRIMP U–Pb zircon geochronological and geochemical data for the Taohong and Xiqiu tonalite–granodiorite stocks from northeastern Zhejiang, southeastern margin of the Yangtze Block. Our data demonstrate that these rocks, dated at 913 ± 15 Ma and 905 ± 14 Ma, are typical amphibole-rich calc-alkaline granitoids formed in an active continental margin. Combined with previously reported isotopic dates for the  1.0 Ga ophiolites and 0.97 Ga adakitic rocks from northeastern Jiangxi, the timing of the Sibao orogenesis is thus believed to be between 1.0 and 0.9 Ga in its eastern segment. It is noted that the Sibao orogeny in South China is in general contemporaneous with some other early Neoproterozoic (1.0–0.9 Ga) orogenic belts such as the Eastern Ghats Belt of India and the Rayner Province in East Antarctica, indicating that the assembly of Rodinia was not finally completed until 0.9 Ga. |
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| Keywords: | SHRIMP U– Pb zircon age Geochemistry Neoproterozoic Granitoids Magmatic arc South China Rodinia |
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