| Zircon U-Pb geochronology,Hf isotopes,and geochemistry constraints on the age and tectonic affinity of the basement granitoids from the Qiongdongnan Basin,northern South China Sea |
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| 作者姓名： | Lijun Mi Xiaoyin Tang Haizhang Yang Shuchun Yang Shuai Guo |
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| 作者单位： | 1. China National Offshore Oil Corporation (CNOOC) Research Center;2. Institute of Geomechanics, Chinese Academy of Geological Sciences;3. Key Laboratory of Paleomagnetism and Tectonic Reconstruction, Ministry of Natural Resources;4. Key Laboratory of Petroleum Geomechanics,China Geological Survey |
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| 基金项目： | The National Natural Science Foundation of China under contract No. 42072181； |
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| 摘 要： | Studies in the northern South China Sea(SCS) basement remain important for understanding the evolution of the Southeast Asian continental margin. Due to a thick cover of sediments and scarce borehole penetration, little is known about the age and tectonic affinity of this basement. In this study, an integrated study of zircon U-Pb geochronology, Hf isotopes, and whole-rock major and trace elements on seven basement granitoids from seven boreholes of Qiongdongnan Basin has been carried out. New z...
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Zircon U-Pb geochronology,Hf isotopes,and geochemistry constraints on the age and tectonic affinity of the basement granitoids from the Qiongdongnan Basin,northern South China Sea |
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| Lijun Mi,Xiaoyin Tang,Haizhang Yang,Shuchun Yang,Shuai Guo.Zircon U-Pb geochronology,Hf isotopes,and geochemistry constraints on the age and tectonic affinity of the basement granitoids from the Qiongdongnan Basin,northern South China Sea[J].Acta Oceanologica Sinica,2023,42(3):19-30. |
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| Authors: | Lijun Mi Xiaoyin Tang Haizhang Yang Shuchun Yang Shuai Guo |
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| Institution: | 1.China National Offshore Oil Corporation (CNOOC) Research Center, Beijing 100028, China2.Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081, China3.Key Laboratory of Paleomagnetism and Tectonic Reconstruction, Ministry of Natural Resources, Beijing 100081, China4.Key Laboratory of Petroleum Geomechanics, China Geological Survey, Beijing 100081, China |
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| Abstract: | Studies in the northern South China Sea (SCS) basement remain important for understanding the evolution of the Southeast Asian continental margin. Due to a thick cover of sediments and scarce borehole penetration, little is known about the age and tectonic affinity of this basement. In this study, an integrated study of zircon U-Pb geochronology, Hf isotopes, and whole-rock major and trace elements on seven basement granitoids from seven boreholes of Qiongdongnan Basin has been carried out. New zircon U-Pb results for these granitoids present middle-late Permian ((270.0±1.2) Ma; (253±3.4) Ma), middle to late Triassic ((246.2±3.4) Ma; (239.3±0.96) Ma; (237.9±0.99) Ma; (228.9±1.0) Ma) and Late Cretaceous ages ((120.6±0.6) Ma). New data from this study, in combination with the previous dataset, indicates that granitoid ages in northern SCS basement vary from 270 Ma to 70.5 Ma, with three age groups of 270–196 Ma, 162–142 Ma, and 137–71 Ma, respectively. Except for the late Paleozoic-Mesozoic rocks in the basement of the northern SCS, a few old zircon grains with the age of (2708.1±17) Ma to (2166.6±19) Ma provide clues to the existence of the pre-Proterozoic components. The geochemical signatures indicate that the middle Permian-early Cretaceous granitoids from the Qiongdongnan Basin are I-type granites formed in a volcanic arc environment, which were probably related to the subduction of the Paleo-Pacific Plate. |
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| Keywords: | Qiongdongnan Basin basement granitoids geochemistry U-Pb and Hf isotopes Paleo-Pacific Plate subduction |
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