Earth's Core-Mantle Boundary: Results of Experiments at High Pressures and Temperatures
- 22 March 1991
- journal article
- research article
- Published by American Association for the Advancement of Science (AAAS) in Science
- Vol. 251 (5000) , 1438-1443
- https://doi.org/10.1126/science.251.5000.1438
Abstract
Laboratory experiments document that liquid iron reacts chemically with silicates at high pressures (≥2.4 × 10 10 Pascals) and temperatures. In particular, (Mg,Fe)SiO 3 perovskite, the most abundant mineral of Earth's lower mantle, is expected to react with liquid iron to produce metallic alloys (FeO and FeSi) and nonmetallic silicates (SiO 2 stishovite and MgSiO 3 perovskite) at the pressures of the core-mantle boundary, 14 × 10 10 Pascals. The experimental observations, in conjunction with seismological data, suggest that the lowermost 200 to 300 kilometers of Earth's mantle, the D′′ layer, may be an extremely heterogeneous region as a result of chemical reactions between the silicate mantle and the liquid iron alloy of Earth's core. The combined thermal-chemical-electrical boundary layer resulting from such reactions offers a plausible explanation for the complex behavior of seismic waves near the core-mantle boundary and could influence Earth's magnetic field observed at the surface.Keywords
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