Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Science 22 March 1991:
Vol. 251. no. 5000, pp. 1438 - 1443
DOI: 10.1126/science.251.5000.1438
Prev | Table of Contents | Next

Articles

Earth's Core-Mantle Boundary: Results of Experiments at High Pressures and Temperatures

ELISE KNITTLE 1 and RAYMOND JEANLOZ 1

1 Department of Geology and Geophysics, University of California, Berkeley, CA 94720

Laboratory experiments document that liquid iron reacts chemically with silicates at high pressures (ge2.4 x 1010 Pascals) and temperatures. In particular, (Mg,Fe)SiO3 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 (SiO2 stishovite and MgSiO3 perovskite) at the pressures of the core-mantle boundary, 14 x 1010 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.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Time-dependent, irreversible entropy production and geodynamics.
K. Regenauer-Lieb, A. Karrech, H. T. Chua, F. G. Horowitz, and D. Yuen (2010)
Phil Trans R Soc A 368, 285-300
   Abstract »    Full Text »    PDF »
Between a rock and a hot place: the core-mantle boundary.
J. Wookey and D. P Dobson (2008)
Phil Trans R Soc A 366, 4543-4557
   Abstract »    Full Text »    PDF »
Discovery of Post-Perovskite and New Views on the Core-Mantle Boundary Region.
K. Hirose and T. Lay (2008)
Elements 4, 183-189
   Abstract »    Full Text »    PDF »
Structure and Dynamics of Earth's Lower Mantle.
E. J. Garnero and A. K. McNamara (2008)
Science 320, 626-628
   Abstract »    Full Text »    PDF »
Effect of water on the phase relations in Earth's mantle and deep water cycle.
K. D. Litasov and E. Ohtani (2007)
Geological Society of America Special Papers 421, 115-156
   Abstract »    Full Text »    PDF »
CORE MANTLE CHEMICAL ISSUES.
D. Walker (2005)
Can Mineral 43, 1553-1564
   Abstract »    Full Text »    PDF »
Effect of A-site cation radius on ordering of BX6 octahedra in (K,Na)MgF3 perovskite.
C. D. Martin, S. Chaudhuri, C. P. Grey, and J. B. Parise (2005)
American Mineralogist 90, 1522-1533
   Abstract »    Full Text »    PDF »
Geochemical Evidence for Excess Iron in the Mantle Beneath Hawaii.
M. Humayun, L. Qin, and M. D. Norman (2004)
Science 306, 91-94
   Abstract »    Full Text »    PDF »
Inferences on Flow at the Base of Earth's Mantle Based on Seismic Anisotropy.
M. Panning and B. Romanowicz (2004)
Science 303, 351-353
   Abstract »    Full Text »    PDF »
Stability of magnesiowustite in Earth's lower mantle.
J.-F. Lin, D. L. Heinz, H.-k. Mao, R. J. Hemley, J. M. Devine, J. Li, and G. Shen (2003)
PNAS 100, 4405-4408
   Abstract »    Full Text »    PDF »
Origins of High-Frequency Scattered Waves near PKKP from Large Aperture Seismic Array Data.
(2002)
Bulletin of the Seismological Society of America 92, 751-760
Seismic Detection of Rigid Zones at the Top of the Core.
S. Rost and J. Revenaugh (2001)
Science 294, 1911-1914
   Abstract »    Full Text »    PDF »
Sediments at the Top of Earth's Core.
B. A. Buffett, E. J. Garnero, and R. Jeanloz (2000)
Science 290, 1338-1342
   Abstract »    Full Text »
Pressure-induced transformations in deep mantle and core minerals.
R. J. Hemley, H. K. Mao, and S. A. Gramsch (2000)
Mineralogical Magazine 64, 157-184
   Abstract »    Full Text »    PDF »
Normal-Mode and Free-Air Gravity Constraints on Lateral Variations in Velocity and Density of Earth's Mantle.
M. Ishii and J. Tromp (1999)
Science 285, 1231-1236
   Abstract »    Full Text »
A Post-Stishovite SiO2 Polymorph in the Meteorite Shergotty: Implications for Impact Events.
T. G. Sharp, A. E. Goresy, B. Wopenka, and M. Chen (1999)
Science 284, 1511-1513
   Abstract »    Full Text »
Compositional Stratification in the Deep Mantle.
L. H. Kellogg, B. H. Hager, and R. D. van der Hilst (1999)
Science 283, 1881-1884
   Abstract »    Full Text »
Three-Dimensional Structure at the Base of the Mantle Beneath the Central Pacific.
L. Bréger and B. Romanowicz (1998)
Science 282, 718-720
   Abstract »    Full Text »
Multivariable Dependence of Fe-Mg Partitioning in the Lower Mantle.
H. Mao, G. Shen, and R. J. Hemley (1997)
Science 278, 2098-2100
   Abstract »    Full Text »
Composition Limits of FexO and the Earth's Lower Mantle.
R. Jeanloz, R. Jeanloz, and R. M. Hazen (1993)
Science 261, 923-924
   PDF »
Response.
V. R. Murthy (1992)
Science 257, 1284-1285
   PDF »
Early Differentiation of the Earth and the Problem of Mantle Siderophile Elements: A New Approach.
V. Rama Murthy and V. R. MURTHY (1991)
Science 253, 303-306
   Abstract »    PDF »


To Advertise     Find Products

Science. ISSN 0036-8075 (print), 1095-9203 (online)