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  2. 地质与地球物理研究所
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  4. 中国科学院地球与行星物理重点实验室
Thermoelastic properties of MgSiO3-majorite at high temperatures and pressures: A first principles study

文献类型：期刊论文

作者Lou, Yancheng1,2,3,4; Stackhouse, Stephen2; Walker, Andrew M.2; Zhang, Zhigang1,3,4
刊名PHYSICS OF THE EARTH AND PLANETARY INTERIORS
出版日期2020-06-01
卷号303页码:11
关键词Majorite Garnet Elastic properties Anisotropy Transition zone First principles
ISSN号0031-9201
DOI10.1016/j.pepi.2020.106491
英文摘要As the major component of garnet, the second most abundant phase in Earth's transition zone, MgSiO3-majorite plays a fundamental role in controlling the state and dynamics of Earth's mantle. However, due to challenges of experiments and simulations, there are still very limited data on the elastic properties of MgSiO3-majorite at simultaneously high temperatures and pressures. In this study, we have carried out extensive first principles calculations to determine the thermoelastic properties of MgSiO3-majorite up to 2000 K and 40 GPa. We find that the elastic constants of MgSiO3-majorite change significantly over the temperature and pressure range studied, with noticeable non-linearities in their pressure dependences. The seismic anisotropy of MgSiO3-majorite is high and generally increases with pressure. It is much higher than that of the other end-members of garnet and ringwoodite, which makes it the most anisotropic mineral in assemblages expected in the lower transition zone. Based on our calculated elastic moduli and with careful elimination of systematic errors, we establish a third-order Birch-Murnaghan-Mie-Gruneisen model for MgSiO3-majorite with the parameters: V-0 = 114.1 cm(3)/mol, K-0 = 163.6 GPa, G(0) = 86.4 GPa, K-0' = 4.44, G(0)' = 1.16, gamma(0) = 1.08, q(0) = 0.48, eta(S0) = 0.76, and theta(0) = 822.5 K. Integrating our results into a thermodynamic model able to predict the properties of mantle assemblages, we find that a pyrolite composition produces velocities that agree with the seismic model AK135 in the upper transition zone. In the lower transition zone, a pyrolite composition fits well with some specific local observations, but a mechanical mixture with 18% basalt and 82% harzburgite is in better agreement with the global seismic model PREM. The much larger abundance of MgSiO3-majorite in the garnet phase of harzburgite suggests that the anisotropy in the lower transition zone may not be negligible and would be observable at least in the heterogeneous zones near subducting slabs.
WOS关键词SINGLE-CRYSTAL ELASTICITY ; TOTAL-ENERGY CALCULATIONS ; EQUATION-OF-STATE ; MAJORITE SOLID-SOLUTION ; PYROPE-MAJORITE ; MOLECULAR-DYNAMICS ; SOUND VELOCITIES ; WAVE VELOCITIES ; HYDROSTATIC COMPRESSION ; CHEMICAL HETEROGENEITY
资助项目Chinese Academy of Sciences[XDB18000000] ; National Natural Science Foundation of China[41590620] ; Natural Environment Research Council[NE/M000044/1]
WOS研究方向Geochemistry & Geophysics
语种英语
WOS记录号WOS:000535988600004
出版者ELSEVIER
资助机构Chinese Academy of Sciences ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; Natural Environment Research Council ; Natural Environment Research Council ; Natural Environment Research Council ; Natural Environment Research Council ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; Natural Environment Research Council ; Natural Environment Research Council ; Natural Environment Research Council ; Natural Environment Research Council ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; Natural Environment Research Council ; Natural Environment Research Council ; Natural Environment Research Council ; Natural Environment Research Council ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; Natural Environment Research Council ; Natural Environment Research Council ; Natural Environment Research Council ; Natural Environment Research Council
源URL[http://ir.iggcas.ac.cn/handle/132A11/96697]  
专题地质与地球物理研究所_中国科学院地球与行星物理重点实验室
通讯作者Zhang, Zhigang
作者单位1.Chinese Acad Sci, Inst Geol & Geophys, Key Lab Earth & Planetary Phys, Beijing 100029, Peoples R China
2.Univ Leeds, Sch Earth & Environm, Leeds LS2 9JT, W Yorkshire, England
3.Chinese Acad Sci, Innovat Acad Earth Sci, Beijing 100029, Peoples R China
4.Univ Chinese Acad Sci, Coll Earth & Planetary Sci, Beijing 100049, Peoples R China
推荐引用方式
GB/T 7714		 Lou, Yancheng,Stackhouse, Stephen,Walker, Andrew M.,et al. Thermoelastic properties of MgSiO3-majorite at high temperatures and pressures: A first principles study[J]. PHYSICS OF THE EARTH AND PLANETARY INTERIORS,2020,303:11.
APA Lou, Yancheng,Stackhouse, Stephen,Walker, Andrew M.,&Zhang, Zhigang.(2020).Thermoelastic properties of MgSiO3-majorite at high temperatures and pressures: A first principles study.PHYSICS OF THE EARTH AND PLANETARY INTERIORS,303,11.
MLA Lou, Yancheng,et al."Thermoelastic properties of MgSiO3-majorite at high temperatures and pressures: A first principles study".PHYSICS OF THE EARTH AND PLANETARY INTERIORS 303(2020):11.

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来源：地质与地球物理研究所

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