Thermoelastic properties of ringwoodite (Fex,Mg1-x)2SiO4: Its relationship to the 520 km seismic discontinuity

被引:36
作者
Nunez Valdez, Maribel [1 ]
Wu, Zhongqing [2 ,3 ]
Yu, Yonggang G. [3 ]
Revenaugh, Justin [4 ]
Wentzcovitch, Renata M. [3 ,5 ]
机构
[1] Univ Minnesota, Sch Phys & Astron, Minneapolis, MN 55414 USA
[2] Univ Sci & Technol China, Sch Earth & Space Sci, Hefei 230026, Anhui, Peoples R China
[3] Univ Minnesota, Dept Chem Engn & Mat Sci, Minneapolis, MN 55414 USA
[4] Univ Minnesota, Dept Earth Sci, Minneapolis, MN 55414 USA
[5] Univ Minnesota, Minnesota Supercomp Inst, Minneapolis, MN 55414 USA
基金
美国国家科学基金会;
关键词
first principles; ringwoodite; elasticity; transition zone; 520 km discontinuity; SINGLE-CRYSTAL ELASTICITY; SOUND VELOCITIES; TRANSITION ZONE; HIGH-PRESSURES; TEMPERATURE-DEPENDENCE; MOLECULAR-DYNAMICS; WADSLEYITE; OLIVINE; MG2SIO4; SPINEL;
D O I
10.1016/j.epsl.2012.07.024
中图分类号
P3 [地球物理学]; P59 [地球化学];
学科分类号
0708 ; 070902 ;
摘要
We combine density functional theory (DFT) within the local density approximation (LDA), the quasiharmonic approximation (QHA), and a model vibrational density of states (VDoS) to calculate elastic moduli and sound velocities of gamma-(Fe-x,Mg1-x)(2)SiO4 (ringwoodite), the most abundant mineral of the lower Earth's transition zone (TZ). Comparison with experimental values at room-temperature and high pressure or ambient-pressure and high temperature shows good agreement with our first-principles findings. Then, we investigate the contrasts associated with the beta ->gamma(Fe-x,Mg1-x)(2)SiO4 transformation at pressures and temperatures relevant to the TZ. This information offers clearly defined reference values to advance the understanding of the nature of the 520 km seismic discontinuity. (C) 2012 Elsevier B.V. All rights reserved.
引用
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页码:115 / 122
页数:8
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