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Melting of a peridotite nodule at high pressures and high water pressures

1968; American Geophysical Union; Volume: 73; Issue: 18 Linguagem: Inglês

10.1029/jb073i018p06023

2156-2202

Ikuo Kushiro, Yasuhiko Syono, Syun-ichi Akimoto,

earthquake and tectonic studies

Journal of Geophysical Research (1896-1977)Volume 73, Issue 18 p. 6023-6029 Melting of a peridotite nodule at high pressures and high water pressures Ikuo Kushiro, Ikuo KushiroSearch for more papers by this authorYasuhiko Syono, Yasuhiko SyonoSearch for more papers by this authorSyun-ichi Akimoto, Syun-ichi AkimotoSearch for more papers by this author Ikuo Kushiro, Ikuo KushiroSearch for more papers by this authorYasuhiko Syono, Yasuhiko SyonoSearch for more papers by this authorSyun-ichi Akimoto, Syun-ichi AkimotoSearch for more papers by this author First published: 15 September 1968 https://doi.org/10.1029/JB073i018p06023Citations: 371AboutPDF 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 Melting of a natural peridotite (spinel-bearing lherzolite) which occurs as a nodule in the tuff of Salt Lake, Hawaii, has been studied at pressures between 1 atm and 50 kb under anhydrous conditions and at pressures between 20 and 60 kb under hydrous conditions with the tetrahedral-anvil type of high-pressure apparatus. Under anhydrous conditions the lherzolite begins to melt near the liquidus of some olivine tholeiites. Garnet is stable near the solidus at pressures higher than at least 30 kb. Under hydrous conditions, when sealed capsules are used, the solidus of the lherzolite is at about 1000°C at 26 kb and about 1150°C at 60 kb. It is 400–700°C lower than the solidus under anhydrous conditions. When unsealed capsules are used, the solidus is raised by 200–400°C from the solidus determined by using sealed capsules. From the present experiments it appears that under anhydrous conditions magmas of olivine tholeiite composition can be formed from lherzolite, but those of quartz-tholeiite composition cannot be formed by partial melting, at least in the pressure range 10–30 kb. Quartz-tholeiite magma, however, can be formed within a much larger pressure range under hydrous conditions. The solidus under hydrous conditions (water pressure is equal to total pressure) would give a possible lowest temperature of beginning of melting of the upper mantle. It is also suggested that the partial melting of the hydrous upper mantle may play an important part in the formation of the low-velocity zone. References Akimoto, S., H. Fujisawa, T. Katsura, The olivine-spinel transition in Fe2SiO4 and Ni2SiO4, J. Geophys. Res., 70, 1969, 1965. Akimoto, S., E. Komada, I. Kushiro, Effect of pressure on the melting of olivine and spinel polymorph of Fe2SiO4, J. Geophys. Res., 72, 679, 1967. Bowen, N. L., J. F. Schairer, The system MgO-FeO-SiO2, Am. J. Sci., 5th ser., 24, 151, 1935. Boyd, F. R., J. L. England, B. T. C. Davis, Effects of pressure on the melting and polymorphism of enstatite, MgSiO3, J. Geophys. Res., 69, 2101, 1964. Green, D. H., A. E. Ringwood, The stability fields of aluminous pyroxene peridotite and garnet peridotite and their relevance in upper mantle structure, Earth Planetary Sci. Letters, 3, 151, 1967a. Green, D. H., A. E. Ringwood, The genesis of basaltic magmas, Contrib. Mineral. Petrol., 15, 103, 1967b. Ito, K., G. C. Kennedy, Melting and phase relations in a natural peridotite to 40 kilobars, Am. J. Sci., 265, 519, 1967. Jeffery, R. N., I. D. Barnett, H. B. Vanfleet, H. T. Hall, Pressure calibration to 100 kbar based on the compression of NaC1, J. Appl. Phys., 37, 3172, 1966. Kuno, H., Mafic and ultramafic nodules in basaltic rocks of Hawaii, Geol. Soc. Am. Mem., 1968. Kushiro, I., Y. Syono, S. Akimoto, Stability of phlogopite at high pressures and possible presence of phlogopite in the earth's upper mantle, Earth Planetary Sci. Letters, 2, 197, 1967. Kushiro, I., H. S. Yoder, M. Nishikawa, Effect of water on the melting of enstatite, Bull. Geol. Soc. Am., 1968. Nockolds, S. R., Average chemical compositions of some igneous rocks, Bull. Geol. Soc. Am., 65, 1007, 1954. Oxburgh, E. R., Petrological evidence for the presence of amphibole in the upper mantle and its petrogenic and geophysical implications, Geol. Mag., 101, 1, 1964. Reay, A., P. G. Harris, The partial fusion of peridotire, Bull. Volcanol., 27, 115, 1964. Ringwood, A. E., A model for the upper mantle, J. Geophys. Res., 67, 857, 1962. Ringwood, A. E., Mineralogy of the mantle, Advances in Earth Science P. Hurley, 357–399, M.I.T. Press, Cambridge, 1966. Wakita, H., H. Nagasawa, S. Uyeda, H. Kuno, Uranium, thorium, and potassium contents in the possible mantle materials, Geochem. J., 1, 183, 1967. Yoder, H. S., C. E. Tilley, Origin of basalt magmas: An experimental study of natural and synthetic rock system, J. Petrol., 3, 342, 1962. Citing Literature Volume73, Issue1815 September 1968Pages 6023-6029 ReferencesRelatedInformation