Chemistry and P-V-T equation of state of FeOH at the base of Earth’s lower mantle and their geophysical implications  

FeO_(2)H_(x)在地球下地幔底部的化学组分、状态方程及其地球物理意义

作　　者：Ruilian Tang Jin Liu Duck Young Kim Ho-Kwang Mao Qingyang Hu Bin Yang Yan Li Chris J.Pickard Richard J.Needs Yu He Haozhe Liu Vitali B.Prakapenka Yue Meng Jinyuan Yan 唐瑞莲;刘锦;Duck Young Kim;毛河光;胡清扬;杨斌;李岩;Chris J.Pickard;Richard J.Needs;何宇;刘浩哲;Vitali B.Prakapenka;孟悦;闫进元(Center for High Pressure Science and Technology Advanced Research,Changchun 130012,China;School of Materials Science and Engineering,Changchun University of Science and Technology,Changchun 130022,China;State Key Laboratory of Superhard Materials,College of Physics,Jilin University,Changchun 130012,China;Department of Materials Science and Metallurgy,University of Cambridge,Cambridge CB30FS,UK;Advanced Institute for Materials Research,Tohoku University,Sendai 980-8577,Japan;Theory of Condensed Matter Group,Cavendish Laboratory,Cambridge CB30HE,UK;Key Laboratory of High-Temperature and High-Pressure Study of the Earth’s Interior,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550081,China;Center for Advanced Radiation Sources,University of Chicago,Chicago IL 60439,USA;X-ray Science Division,Argonne National Laboratory,Argonne IL 60439,USA;Material Science Division,Lawrence Berkeley National Laboratory,Berkeley CA 94720,USA;CAS Center for Excellence in Deep Earth Science,Guangzhou 510640,China)

机构地区：[1]Center for High Pressure Science and Technology Advanced Research,Changchun 130012,China [2]School of Materials Science and Engineering,Changchun University of Science and Technology,Changchun 130022,China [3]State Key Laboratory of Superhard Materials,College of Physics,Jilin University,Changchun 130012,China [4]Department of Materials Science and Metallurgy,University of Cambridge,Cambridge CB30FS,UK [5]Advanced Institute for Materials Research,Tohoku University,Sendai 980-8577,Japan [6]Theory of Condensed Matter Group,Cavendish Laboratory,Cambridge CB30HE,UK [7]Key Laboratory of High-Temperature and High-Pressure Study of the Earth’s Interior,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550081,China [8]Center for Advanced Radiation Sources,University of Chicago,Chicago IL 60439,USA [9]X-ray Science Division,Argonne National Laboratory,Argonne IL 60439,USA [10]Material Science Division,Lawrence Berkeley National Laboratory,Berkeley CA 94720,USA [11]CAS Center for Excellence in Deep Earth Science,Guangzhou 510640,China

出　　处：《Science Bulletin》2021年第19期1954-1958,M0003,共6页科学通报（英文版）

基　　金：supported by the National Key Research and Development Program of China(2019YFA0708502);the support of the National Natural Science Foundation of China(12104065);the Youth Science Foundation of Changchun University of Science and Technology(XQNJJ-201815)supported by the National Science Associated Funding Grant(U1530402);supported by National Science Foundation(NSF)(EAR-1722515,EAR-1447438);the support by the National Natural Science Foundation of China(11774015);supported by the China Academy of Engineering Physics Research Project(CX20210048);a Tencent Xplorer Prize;supported by the Royal Society through a Royal Society Wolfson Research Merit award and the Engineering and Physical Sciences Research Council(EP/P022596/1)。

摘　　要：The hydrogen-absorbing ability of a mantle mineral in its structure determines the capacity of the water reservoirs hosted by the mineral. Water reservoirs at the base of Earth’s mantle directly influence the fate of water brought down by slab subduction and the seismic heterogeneity such as ultralow-velocity zones(ULVZs)at the core-mantle boundary. Pyrite-Fe O2 Hx(0≤x ≤1) presents a possibility of such reservoirs in the deep mantle [1–3].水(氢)从地表到地球深部的输运、循环过程及其对地震传播速度的影响是当前地球科学研究的热点.近期发现的黄铁矿结构FeO_(2)H_(x)是下地幔中罕见的含水矿物之一.它在下地幔温压条件下的化学组分以及弹性性质将直接影响地球深部的水循环过程以及核幔边界的地震波速.但自从这个新相被发现以来,它在下地幔条件下的稳定性以及化学组分一直存在争议.本研究在下地幔温压条件下对黄铁矿结构FeO_(2)H_(x)进行脱氢反应动力学实验,并对同步辐射X射线衍射数据进行P-V-T状态方程分析.我们认为该矿物以部分脱氢的形式存在于地幔深处,而不是FeO2或FeO2H.本研究还从地震横波与纵波波速降低比率的角度阐明了由黄铁矿FeO_(2)H_(x)和部分熔融导致的不同超低速带之间的差别.

关 键 词：地球科学研究 地球深部 地球物理 核幔边界 同步辐射X射线衍射 弹性性质 下地幔 化学组分 

分 类 号：P542.5[天文地球—构造地质学] P59[天文地球—地质学]