Title: Effects of pressure on the melting and polymorphism of enstatite, MgSiO<sub>3</sub>
Abstract: Journal of Geophysical Research (1896-1977)Volume 69, Issue 10 p. 2101-2109 Effects of pressure on the melting and polymorphism of enstatite, MgSiO3 F. R. Boyd, F. R. BoydSearch for more papers by this authorJ. L. England, J. L. EnglandSearch for more papers by this authorBrian T. C. Davis, Brian T. C. DavisSearch for more papers by this author F. R. Boyd, F. R. BoydSearch for more papers by this authorJ. L. England, J. L. EnglandSearch for more papers by this authorBrian T. C. Davis, Brian T. C. DavisSearch for more papers by this author First published: 15 May 1964 https://doi.org/10.1029/JZ069i010p02101Citations: 191AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat Abstract The melting curve of enstatite, MgSiO3, has been determined in the pressure range 5 to 46 kb. The data can be fitted by a smooth curve originating at the incongruent melting point at atmospheric pressure (1557°C). Simon constants for this curve are A = 28.5 and c = 5.01. The initial slope is 12.8 deg/kb, but it flattens to about 6 deg/kb in the range 40 to 50 kb. The melting curve is intersected by the polymorphic transition protoenstatite ⇄ rhombic enstatite, with rhombic enstatite as the high-pressure phase. The transition curve is approximately T = 985°C + 84P (kb), with the triple point protoenstatite-rhombic enstatite-liquid at 1650°C and 8.0 kb. Enstatite melts congruently at high pressure. Experimental data show that the pressure at which the melting changes from incongruent to congruent must be less than 5.4 kb. Thermodynamic calculations indicate that it is probably about 2.3 kb. These data suggest that rocks which show textural evidence of an olivine-liquid reaction relation have developed this relation at relatively shallow depth, probably less than about 9 km. References Atlas, L., The polymorphism of MgSiO3 and solid-state equilibria in the system MgSiO3-CaMgSi2O6, J. Geol., 60, 125–147, 1952. Bowen, N. L., The Evolution of the Igneous Rocks, Princeton University Press, 1928. Bowen, N. L., O. Andersen, The binary system MgO-SiO2, Am. J. Sci., 37, 487–500, 1914. Bowen, N. L., J. F. Schairer, The system MgO-FeO-SiO2, Am. J. Sci., 29, 151–217, 1935. Boyd, F. R., J. L. England, Mantle minerals, Carnegie Inst. Wash. Yr. Book, 61, 107–112, 1962. Boyd, F. R., J. L. England, Effect of pressure on the melting of diopside, CaMgSi2O6, and albite, NaAlSi3O8, in the range up to 50 kilobars, J. Geophys. Res., 68, 311–323, 1963. Boyd, F. R., J. F. Schairer, The system MgSiO3-CaMgSi2O6, J. Petrol., 1964. Davis, B. T. C., J. L. England, Melting of forsterite, Mg2SiO4, at pressures up to 47 kilobars, J. Geophys. Res., 1964. Eaton, J. P., K. J. Murata, How volcanoes grow, Science, 132, 925–938, 1960. Foster, W. R., High-temperature X-ray diffraction study of the polymorphism of MgSiO3, J. Am. Ceram. Soc., 34, 255–259, 1951. Griggs, D. T., F. S. Turner, H. C. Heard, Deformation of rocks at 500°-800°C, Geol. Soc. Am. Mem., 79, 39–104, 1960. Hess, H. H., Stillwater igneous complex, Montana, Geol. Soc. Am. Mem., 80, 230, 1960. Kushiro, I., A possible origin of tholeiitic magma, Japan. J. Geol. Geography, 32, 31–37, 1961. Matsumoto, T., Pressure effects on phase equilibria in some principal rock-forming minerals—proposal of a model regarding the origin of primary magmas, J. Geosciences, Osaka City Univ., 7, 81–95, 1963. Milton, D. J., P. S. DeCarli, Muskelynite: Formation by explosive shock, Science, 140, 670–671, 1963. O'Hara, M. J., The join diopside-pyrope at 30 kb, Carnegie Inst. Wash. Yr. Book, 62, 116–118, 1963. Powers, H. A., Composition and origin of basaltic magma of the Hawaiian Islands, Geochim. Cosmochim. Acta, 7, 77–107, 1955. Ringwood, A. E., M. Seabrook, High-pressure phase transformations in germanate pyroxenes and related compounds, J. Geophys. Res., 68, 4601–4609, 1963. Verhoogen, J., Petrological evidence on temperature distribution in the mantle of the earth, Trans. Am. Geophys. Union, 35, 85–92, 1954. Citing Literature Volume69, Issue1015 May 1964Pages 2101-2109 ReferencesRelatedInformation
Publication Year: 1964
Publication Date: 1964-05-15
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 217
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