Oxidation of arcs and mantle wedges by reduction of manganese in pelagic sediments during seafloor subduction

doi:10.2138/am-2022-8171

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	Oxidation of arcs and mantle wedges by reduction of manganese in pelagic sediments during seafloor subduction
	Song, Shuguang 3; Ye, Shiting 3; Allen, Mark B.2; Niu, Yaoling 2; Sun, Weidong 1; Zhang, Lifei 3
刊名	AMERICAN MINERALOGIST
	2022-10-26
卷号	107 期号:10 页码:1850-1857
关键词	Ferromanganese pelagic sediments high-pressure metamorphism reductive reactions subduction zone mantle oxidation
ISSN号	0003-004X
DOI	10.2138/am-2022-8171
通讯作者	Song, Shuguang(sgsong@pku.edu.cn)
英文摘要	Plate subduction links the Earth's surface and interior and may change the redox state of the Earth's mantle. Mantle wedges above subduction zones have high oxygen fugacity compared with other mantle reservoirs, but the cause is debated. Here we analyze high-pressure metamorphic rocks derived from ferromanganese pelagic sediments in the Qilian subduction complex, northwest (NW) China. We show that progressive metamorphism is a process of reducing reactions, in which Mn4+ is reduced to Mn2+. On the global scale, such reactions would release significant amounts of oxygen (similar to 1.27 x 10(12) g year(-1)) estimated from the global flux of MnO in sediments passing into subduction zones. This budget is sufficient to raise the oxygen fugacity of the mantle wedge, hence arc magmas, to a higher level than other mantle reservoirs. In contrast, ferric iron (Fe3+) enters hematite, aegirine, and garnet, without valence change and plays little role in the oxidation of the mantle wedge. Fe3+ remains stable to depths of >100 km but will transfer to the deeper mantle along with the subducting slab. The manganese reduction process provides a new explanation for high oxygen fugacity in the mantle wedge.
资助项目	National Key Research and Development Program of China[2019YFA0708503] ; National Natural Science Foundation of China[91955202]
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
语种	英语
出版者	MINERALOGICAL SOC AMER
WOS记录号	WOS:000860851300003
内容类型	期刊论文
源URL	[http://ir.qdio.ac.cn/handle/337002/180753]
专题	海洋研究所_深海极端环境与生命过程研究中心
通讯作者	Song, Shuguang
作者单位	1.Chinese Acad Sci, Ctr Deep Sea Res, Inst Oceanog, Qingdao 266071, Peoples R China 2.Univ Durham, Dept Earth Sci, Durham DH1 3LE, England 3.Peking Univ, Sch Earth & Space Sci, MOE Key Lab Orogen Belt & Crustal Evolut, Beijing 100871, Peoples R China
推荐引用方式 GB/T 7714	Song, Shuguang,Ye, Shiting,Allen, Mark B.,et al. Oxidation of arcs and mantle wedges by reduction of manganese in pelagic sediments during seafloor subduction[J]. AMERICAN MINERALOGIST,2022,107(10):1850-1857.
APA	Song, Shuguang,Ye, Shiting,Allen, Mark B.,Niu, Yaoling,Sun, Weidong,&Zhang, Lifei.(2022).Oxidation of arcs and mantle wedges by reduction of manganese in pelagic sediments during seafloor subduction.AMERICAN MINERALOGIST,107(10),1850-1857.
MLA	Song, Shuguang,et al."Oxidation of arcs and mantle wedges by reduction of manganese in pelagic sediments during seafloor subduction".AMERICAN MINERALOGIST 107.10(2022):1850-1857.