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The composition of the terrestrial planets

Anderson, Don L. and Kovach, Robert L. (1967) The composition of the terrestrial planets. Earth and Planetary Science Letters, 3 (1). pp. 19-24. ISSN 0012-821X.

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The mean atomic weight is a useful parameter with which to discuss the composition of the terrestrial planets. Using the density-pressure relationships of the earth and assigning a mean atomic weight to the mantle and core with the help of shock wave data, it is possible to construct a mass-mean density curve for planets of a given mean atomic weight. The Mariner IV occultation experiment and recent telescopic measurements have provided new data for the radius of Mars which are in substantial agreement and yield a density for Mars between 3.96 and 4.10 g/cm^3. Planetary radar data have been processed to yield improved estimates of the radii and masses of Venus and Mercury. The corresponding densities are ϱ (Venus) = 5.27 and ϱ (Mercury) = 5.50 g/cm^3. These new determinations of density are used to estimate the mean atomic weight of the terrestrial planets. The results are Mars, 25.3 ± 0.4; Venus. 26.4; Mercury, 36; and the moon 22.0. The mean atomic weight of the earth is 27.0. These results can be compared with the following representative values for meteorites and terrestrial rocks: igneous rocks, 21–22; carbonaceous chondrites, 23.4–24.0; ordinary chondrites 24.4; “high iron” chondrites, 25.1; enstatite chondrites, 25.6; and iron meteorites, 55.

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Additional Information:© 1967 North-Holland Publishing Company, Amsterdam. Received 30 June 1967. This work was supported by the National Aeronautics and Space Administration, Contract No. NSR-24-005-047 and the Sloan Foundation. This study represents Contribution No. 1429, Division of Geological Sciences, California Institute of Technology, Pasadena, California.
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Sloan FoundationUNSPECIFIED
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Caltech Division of Geological Sciences1429
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Official Citation:Don L. Anderson, Robert L. Kovach, The composition of the terrestrial planets, Earth and Planetary Science Letters, Volume 3, 1967–1968, Pages 19-24, ISSN 0012-821X, (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:45339
Deposited By: Ruth Sustaita
Deposited On:30 Apr 2014 17:10
Last Modified:03 Oct 2019 06:29

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