Advances in Earth Science ›› 2017, Vol. 32 ›› Issue (2): 111-127. doi: 10.11867/j.issn.1001-8166.2017.02.0111

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Some Key Problems on the Petrogenesis of Seafloor Basalts, Abyssal Peridotites and Geodynamics—A Non-traditional Isotope Approach

Yaoling Niu 1, 2, 3( ), Hongmei Gong 1, 2, Xiaohong Wang 1, 2, Yuanyuan Xiao 1, 2, Pengyuan Guo 1, 2, Fengli Shao 1, 2, 4, Pu Sun 1, 2, 4, Shuo Chen 1, 2, 4, Meng Duan 1, 2, 5, Juanjuan Kong 1, 2, 4, Guodong Wang 1, 2, Qiqi Xue 1, 2, 5, Yajie Gao 1, 2, 4, Di Hong 1, 2, 4   

  1. 1.Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
    2.Qingdao National Laboratory for Marine Science and Technology, Qingdao 266061,China
    3.Department of Earth Sciences, Durham University, Durham DH1 3LE,UK
    4.University of Chinese Academy of Sciences, Beijing 100049, China
    5.China University of Geosciences, Beijing 100083, China
  • Received:2016-12-13 Revised:2017-01-20 Online:2017-02-20 Published:2017-02-20
  • About author:

    First author:Niu Yaoling(1959-), male, Lintao County, Gansu Province, Porfessor. Research areas include petrology, geochemistry, global tectonics and chemical

  • Supported by:
    Project supported by the National Natural Science Foundation of China “Some key problems on the petrogenesis of seafloor basalts, abyssal peridotites and geodynamics—A non-traditional isotope approach” (No.41630968)

Yaoling Niu, Hongmei Gong, Xiaohong Wang, Yuanyuan Xiao, Pengyuan Guo, Fengli Shao, Pu Sun, Shuo Chen, Meng Duan, Juanjuan Kong, Guodong Wang, Qiqi Xue, Yajie Gao, Di Hong. Some Key Problems on the Petrogenesis of Seafloor Basalts, Abyssal Peridotites and Geodynamics—A Non-traditional Isotope Approach[J]. Advances in Earth Science, 2017, 32(2): 111-127.

This paper discusses some major research to be carried out in the next five years in the newly established Laboratory of Ocean Lithosphere and Mantle Geodynamics. By using our existing sample collections of global mid-ocean ridge basalts, gabbros and abyssal peridotites from the Pacific, Atlantic and Indian oceans, the research includes: ①Using Ti-Zr-Hf stable isotope methods to test the hypothesis that the observed huge Nb-Ta and Zr-Hf fractionations result from mass-dependent fractionation under mantle magmatic conditions; ②Using a MORB sample suite of uniform ratios of incompatible elements and Sr-Nd-Pb isotopes with large major element compositional variation to test the common hypothesis of iron isotope fractionation, i.e, the affinity of heavy Fe with ferric Fe (Fe3+), and both heavy Fe and ferric Fe (Fe3+) being more incompatible than light Fe and ferrous Fe (Fe2+) during magma evolution; while using an incompatible trace element and Sr-Nd-Pb isotope highly variable MORB suite to test the same hypothesis during low-degree mantle melting (i.e, the effect of mantle metasomatism); ③Proposing and testing the hypothesis that the high oxygen fugacity of the Earth’s mantle is a consequence of plate tectonics by subducting partially serpentinized oceanic mantle lithosphere with abundant ferric Fe (e.g. Fe3+/SFe>2); ④The recent work by Andersen et al. (Nature, 2015) is a milestone contribution by using U isotope variation in oceanic basalts to hypothesize that the O2-rich atmosphere since the late Archean (abont 2.4 Ga) mobilized the water soluble U (6+ vs. 4+) from continents, transported to the ocean and subducted with sediments to the upper mantle, which explains the low Th/U in MORB (<2.5) and the high Th/U (>3.5) ocean island basalts (OIB) do not see such U addition effect probably because OIB source materials are all ancient (> abont 2.4 Ga) if there were subducted component. The Cenozoic alkali basalts from eastern China are ideal materials for evaluating the significance of the subducted seafloor materials for the petrogenesis of OIB and enriched MORB by using the U isotope approach, which is expected to revise and improve the Andersen et al hypothesis.

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