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MgSiO3 perovskite: a HRTEM study

Published online by Cambridge University Press:  05 July 2018

Ishmael Hassan
Affiliation:
Department of Geology, Faculty of Science, University of Kuwait, P. O. Box 5969, Safat, Kuwait, 13060
Yasuhiro Kudoh
Affiliation:
Department of Petrology, Mineralogy, and Economic Geology, University of Tohoku, Aobaku, Sendai 980, Japan
Peter R. Buseck
Affiliation:
Departments of Geology and Chemistry, Arizona State University, Tempe, Arizona 85287, U.S.A.
Eui Ito
Affiliation:
Institute for Study of the Earth's Interior, Okayama University, Misasa, Tottori 682-02, Japan

Abstract

Selected-area electron diffraction patterns for the [110] zone of MgSiO3 perovskite are consistent with the orthorhombic unit cell obtained by X-ray diffraction (a = 4.775, b = 4.929, c = 6.897 Å). Various areas of a crystal fragment show diffuse streaking along c*, and well-developed satellite reflections that give a 3-fold repeat along [10]*. Another fragment shows doubled cell dimensions when viewed down [30]. The variable occurrence of the satellite reflectioncs and diffuse streaking indicate subtle variations in ordering, chemistry, or both. Images obtained by high-resolution transmission electron microscopy contain perfectly ordered regions, out-of-phase boundaries, and intergrowths of the two orthorhombic forms of perovskite.

Type
Mineralogy
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1996

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References

Hassan, I., Kudoh, Y., Buseck, P.R. and Ito, E. (1988) MgSi03 Perovskite: a HRTEM Study. EOS: Trans. Amer. Geophys. Union, 69, 1436.Google Scholar
Hazen, R.M. (1988) AGU Chapman Conference on Perovskites. EOS: Trans. Am. Geophys. Union, 69, 28.CrossRefGoogle Scholar
Horiuchi, H., Ito, E. and Weidner, D.J. (1987) MgSi03 (perovskite-type): single crystal X-ray diffraction study. Amer. Mineral, 72, 357–60.Google Scholar
Ito, E. and Matsui, Y. (1978) Synthesis and crystal-chemical characterization of MgSiO3 perovskite. Earth Planet Sci. Lett., 38, 443–50.CrossRefGoogle Scholar
Jeanloz, R. and Thompson, A.B. (1983) Phase transitions and mantle discontinuities. Rev. Geophys, Space Sci., 21 51—74.CrossRefGoogle Scholar
Kudoh, Y., Ito, E. and Takeda, H. (1987) Effect of pressure on the crystal structure of perovsldte-type MgSi03. Phys. Chem. Minerals, 14, 350–4.CrossRefGoogle Scholar
Liu, L.G. (1974) Silicate perovskite from phase transformations of pyrope-garnet at high pressure and temperature. Geophys. Res. Lett., 1, 277–80.CrossRefGoogle Scholar
Liu, L.G. (1975) Post-oxide phases of fosterite and enstatite. Geophys. Res. Lett., 2, 417–9.CrossRefGoogle Scholar
Liu, L.G. (1979) Calculations of high-pressure phase transitions in the system MgO-Si02 and implications for mantle discontinuities. Phys. Earth Planet Inter., 19, 319-30.Google Scholar
Madon, M., Bell, P.M., Mao, H.K. and Poirier, J.P. (1980) Transmission electron diffraction and microscopy of synthetic high pressure MgSi03 phase with perovskite structure. Geophys. Res. Lett., 1, 629—32.Google Scholar
Reid, A.F. and Ringwood, A.E. (1975) High-pressure modification of ScA103 and some geophysical implications. J. Geophys. Res., 80, 3363–70.CrossRefGoogle Scholar
Van Tendeloo, G., Ghose, S. and Amelinckx, S. (1989) A dynamical model for the phase transition in anorthite, CaAl2Si2O8- I- Evidence from electron microscopy. Phys. Chem. Minerals, 16, 311–9.CrossRefGoogle Scholar
Wang, Y. and Liebermann, R.C. (1993) Electron microscopy study of domain structure due to phase transitions in natural perovskite. Phys. Chem. Minerals, 20, 147–58.CrossRefGoogle Scholar
Yagi, T., Mao, H.K. and Bell, M. (1978) Structure and crystal chemistry of perovskite-type MgSi03. Phys. Chem. Minerals, 3, 97110.CrossRefGoogle Scholar