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Mantle Redox State Evolution in Eastern China and Its Implications
Author(s) -
Jianping LI,
Jian WANG
Publication year - 2002
Publication title -
acta geologica sinica ‐ english edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 61
eISSN - 1755-6724
pISSN - 1000-9515
DOI - 10.1111/j.1755-6724.2002.tb00089.x
Subject(s) - mantle (geology) , mineral redox buffer , geology , craton , lithosphere , geochemistry , olivine , transition zone , xenolith , asthenosphere , hotspot (geology) , mantle convection , spinel , china , basalt , geophysics , paleontology , tectonics , political science , law
Using the secondary spinel standard, the authors have precisely measured the Fe 3+ /Σ Fe values of spinels in mantle xenoliths from Cenozoic basalts in eastern China, and estimated the oxygen fugacities recorded by 63 mantle xenoliths through olivine‐orthopyroxene‐spinel oxygen barometry. The results indicate that the oxygen fugacities of the lithospheric mantle in eastern China are higher in the south than in the north. Among them, the oxygen fugacity of the North China craton lithospheric mantle is the lowest, similar to that of the oceanic mantle, while that of Northeast and South China are the same as that of the global continental mantle. The variations of mantle redox state in eastern China are mainly controlled by the C‐O‐H fluids derived from the asthenospheric mantle. According to the mantle oxidation state, it can be concluded that the C‐O‐H fluids in the lithospheric mantle of eastern China consist mainly of CO 2 and minor H 2 O, but CH 4 ‐rich fluids should come from the asthenosphere where the oxidation state is lower.