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Science 7 March 1980:
Vol. 207. no. 4435, pp. 1035 - 1041
DOI: 10.1126/science.207.4435.1035
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Articles

Dynamic Compression of Earth Materials

Thomas J. Ahrens 1

1 Professor of geophysics at the Seismological Laboratory, Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena 91125

Shock wave techniques have been used to investigate the pressuredensity relations of metals, silicates, and oxides over the entire range of pressures present in the earth (3.7 x 106 bars at the center). In many materials of geophysical interest, such as iron, wüstite, calcium oxide, and forsterite, major shock-induced phase changes dominate the compression behavior below pressures of 106 bars. The shock wave data for the high-pressure phases of these minerals lead to important inferences about the composition of the lower mantle and outer, liquid core of the earth. The lower mantle of the earth appears to have a slightly higher density than is inferred to correspond to the behavior of an olivine-rich assembiage of the same composition as the upper mantle. The core has a density some 10 percent less than that of pure iron and may have 9 to 12 percent sulfur or about 8 percent oxygen by weight.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Models of the Earth's Core.
D. J. Stevenson and D. J. Stevenson (1981)
Science 214, 611-619
   Abstract »    PDF »
Association Reaction in Forsterite Under Shock Compression.
Y. Syono, Y. SYONO, T. GOTO, H. TAKEI, M. TOKONAMI, and K. NOBUGAI (1981)
Science 214, 177-179
   Abstract »    PDF »


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