The strength of Mg0.9Fe0.1SiO3 perovskite at high pressure and temperature

被引:68
作者
Chen, JH [1 ]
Weidner, DJ
Vaughan, MT
机构
[1] SUNY Stony Brook, Inst Mineral Phys, Stony Brook, NY 11794 USA
[2] SUNY Stony Brook, Dept Geosci, Stony Brook, NY 11794 USA
基金
美国国家科学基金会; 加拿大健康研究院;
关键词
D O I
10.1038/nature01130
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
The Earth's lower mantle consists mainly of (Mg,Fe)SiO(3) perovskite and (Mg,Fe)O magnesiowustite, with the perovskite taking up at least 70 per cent of the total volume(1). Although the rheology of olivine, the dominant upper-mantle mineral, has been extensively studied, knowledge about the rheological behaviour of perovskite is limited. Seismological studies indicate that slabs of subducting oceanic lithosphere are often deflected horizontally at the perovskite-forming depth, and changes in the Earth's shape and gravity field during glacial rebound indicate that viscosity increases in the lower part of the mantle. The rheological properties of the perovskite may be important in governing these phenomena. But (Mg,Fe)SiO(3) perovskite is not stable at high temperatures under ambient pressure, and therefore mechanical tests on (Mg,Fe)SiO(3) perovskite are difficult. Most rheological studies of perovskite have been performed on analogous materials(2-7), and the experimental data on (Mg,Fe)SiO(3) perovskite are limited to strength measurements at room temperature in a diamond-anvil cell(8) and microhardness tests at ambient conditions(9). Here we report results of strength and stress relaxation measurements of (Mg(0.9)Fe(0.1))SiO(3) perovskite at high pressure and temperature. Compared with the transition-zone mineral ringwoodite(10) at the same pressure and temperature, we found that perovskite is weaker at room temperature, which is consistent with a previous diamond-anvil-cell experiment(8), but that perovskite is stronger than ringwoodite at high temperature.
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页码:824 / 826
页数:4
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