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Self-diffusion of oxygen and silicon in MgSiO3 perovskite
被引:47
|作者:
Dobson, David P.
[1
]
Dohmen, Ralf
[2
]
Wiedenbeck, Michael
[3
]
机构:
[1] UCL, Dept Earth Sci, London WC1E 6BT, England
[2] Ruhr Univ Bochum, Inst Geol Mineral & Gepohys, D-44801 Bochum, Germany
[3] Geoforschungszentrum Potsdam, D-14473 Potsdam, Germany
关键词:
MgSiO3;
perovskite;
O diffusion;
Si diffusion;
lower mantle;
chemical equilibration;
high-pressure;
D O I:
10.1016/j.epsl.2008.03.029
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 present results of simultaneous measurements of self-diffusion of oxygen and silicon in magnesium silicate perovskite. Oxygen diffusion is similar to 2 orders of magnitude faster than Si self-diffusion and Fe-Mg interdiffusion in perovskite, with D(0) = 9.16 x 10(-4) (+0.16/-9.2 X 10(-6)) m(2)/s and Q = 501 +/- 80 kJ/mol at 25 GPa. Despite this high 0 diffusivity, however, the electrical conductivity of the lower mantle will be dominated by electronic conduction and the present-day core is likely to be out of redox equilibrium with the mantle. (C) 2008 Elsevier B.V. All rights reserved.
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页码:125 / 129
页数:5
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