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DOI	10.1016/j.scib.2020.12.016
	Sub-basin scale inhomogeneity of mantle in the South China Sea revealed by magnesium isotopes
	Zhong Y.; Zhang G.-L.; Jin Q.-Z.; Huang F.; Wang X.-J.; Xie L.-W.
发表日期	2021
ISSN	20959273
起始页码	740
结束页码	748
卷号	66 期号:7
英文摘要	The South China Sea (SCS) is the largest extensional basin in the western Pacific and was formed after rifting of the Euro–Asian continental margin. The nature of its underlying mantle remains enigmatic due to the lack of sampling of the seafloor's igneous crust. The International Ocean Discovery Program Expedition 349 cored seafloor basalts of the southwestern (Site U1433) and eastern (Site U1431) SCS sub-basins. The recovered basalt samples exhibit different source lithologies and geochemistries. The Mg isotopic compositions of seafloor basalts from these sites were investigated to elucidate the origin of this large-scale mantle inhomogeneity. Results indicate that the Site U1431 basalts have a mantle-like average δ26Mg value of –0.27‰ ± 0.06‰ (2SD; n = 10). Together with inhomogeneous Sr–Nd–Pb–Hf isotopic compositions, the Site U1433 basalts have an average δ26Mg value (–0.20‰ ± 0.06‰; 2SD; n = 8) higher than those of the Site U1431 basalts and normal mantle. Their heavier Mg isotopic compositions and low 206Pb/204Pb ratios (~17.7) indicate that the Site U1433 basalts were affected by the re-melting of detached continental-arc lithosphere in the sub-ridge mantle. The coupling of Mg and Sr–Nd isotopes provides robust evidence that the mantle-like δ26Mg values of the Site U1431 basalts resulted from mixing between detached continental arc lithosphere and the nearby Hainan plume, with respective supra- and sub-normal δ26Mg values. From the perspective of Mg isotope, the mantles of the southwestern and eastern sub-basins are compositionally inhomogeneous, with their mantle evolutionary histories being distinct. © 2020 Science China Press
关键词	Hainan plume Magnesium isotope Mantle heterogeneity Mid-ocean-ridge basalt South China Sea
英文关键词	Basalt; Isotopes; Continental margin; Evolutionary history; Inhomogeneities; Isotopic composition; Magnesium isotopes; South China sea; Sub-basin scale; Western Pacific; Magnesium
语种	英语
来源期刊	Science Bulletin
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/207694
作者单位	Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China; Laboratory for Marine Geology, National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266237, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, 266071, China; CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, 230026, China; State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi'an, 710069, China; State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China
推荐引用方式 GB/T 7714	Zhong Y.,Zhang G.-L.,Jin Q.-Z.,et al. Sub-basin scale inhomogeneity of mantle in the South China Sea revealed by magnesium isotopes[J],2021,66(7).
APA	Zhong Y.,Zhang G.-L.,Jin Q.-Z.,Huang F.,Wang X.-J.,&Xie L.-W..(2021).Sub-basin scale inhomogeneity of mantle in the South China Sea revealed by magnesium isotopes.Science Bulletin,66(7).
MLA	Zhong Y.,et al."Sub-basin scale inhomogeneity of mantle in the South China Sea revealed by magnesium isotopes".Science Bulletin 66.7(2021).