The postspinel phase boundary in Mg2SiO4 determined by in situ X-ray diffraction

Science

Volumn 279, Issue 5357, 1998, Pages 1698-1700

  Irifune, Tetsuo ^a   Nishiyama, Norimasa ^a   Kuroda, Koji ^a   Inoue, Toru ^a   Isshiki, Maiko ^a   Utsumi, Wataru ^b   Funakoshi, Ken Ichi ^c   Urakawa, Satoru ^d   Uchida, Takeyuki ^e   Katsura, Tomoo ^d   Ohtaka, Osamu ^f  

^a EHIME UNIVERSITY   (Japan)

^b JAPAN ATOMIC ENERGY AGENCY   (Japan)

^c JAPAN SYNCHROTRON RADIATION RESEARCH INSTITUTE   (Japan)

^d OKAYAMA UNIVERSITY   (Japan)

^e UNIVERSITY OF TOKYO   (Japan)

^f OSAKA UNIVERSITY   (Japan)

Author keywords

[No Author keywords available]

Indexed keywords

MAGNESIUM DERIVATIVE; MAGNESIUM OXIDE; MINERAL;

PERICLASE; PEROVSKITE; PHASE BOUNDARY; SPINEL; XRD;

ARTICLE; MICROANALYSIS; PRESSURE; PRIORITY JOURNAL; TEMPERATURE; THERMODYNAMICS; X RAY DIFFRACTION;

EID: 7144251881     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.279.5357.1698     Document Type: Article

References (31)

1. A. E. Ringwood and A. Major, Earth Planet. Sci. Lett. 1, 241 (1966); S. Akimoto and H. Fujisawa, J. Geophys. Res. 73, 1467 (1968); L. Liu, Nature 262, 770 (1976).
2. A. E. Ringwood and A. Major, Earth Planet. Sci. Lett. 1, 241 (1966); S. Akimoto and H. Fujisawa, J. Geophys. Res. 73, 1467 (1968); L. Liu, Nature 262, 770 (1976).
3. A. E. Ringwood and A. Major, Earth Planet. Sci. Lett. 1, 241 (1966); S. Akimoto and H. Fujisawa, J. Geophys. Res. 73, 1467 (1968); L. Liu, Nature 262, 770 (1976).
4. N. Kawai, S. Endo, K. Ito, Phys. Earth Planet. Int. 3, 182 (1970); K. Suito, J. Phys. Earth 20, 225 (1972); C. R. Bina and B. J. Wood, J. Geophys. Res. 92, 4853 (1987); T. Katsura and E. Ito, ibid. 94, 15663 (1989); M. Akaogi and E. Ito, ibid., p. 15671.
5. N. Kawai, S. Endo, K. Ito, Phys. Earth Planet. Int. 3, 182 (1970); K. Suito, J. Phys. Earth 20, 225 (1972); C. R. Bina and B. J. Wood, J. Geophys. Res. 92, 4853 (1987); T. Katsura and E. Ito, ibid. 94, 15663 (1989); M. Akaogi and E. Ito, ibid., p. 15671.
6. N. Kawai, S. Endo, K. Ito, Phys. Earth Planet. Int. 3, 182 (1970); K. Suito, J. Phys. Earth 20, 225 (1972); C. R. Bina and B. J. Wood, J. Geophys. Res. 92, 4853 (1987); T. Katsura and E. Ito, ibid. 94, 15663 (1989); M. Akaogi and E. Ito, ibid., p. 15671.
7. N. Kawai, S. Endo, K. Ito, Phys. Earth Planet. Int. 3, 182 (1970); K. Suito, J. Phys. Earth 20, 225 (1972); C. R. Bina and B. J. Wood, J. Geophys. Res. 92, 4853 (1987); T. Katsura and E. Ito, ibid. 94, 15663 (1989); M. Akaogi and E. Ito, ibid., p. 15671.
8. N. Kawai, S. Endo, K. Ito, Phys. Earth Planet. Int. 3, 182 (1970); K. Suito, J. Phys. Earth 20, 225 (1972); C. R. Bina and B. J. Wood, J. Geophys. Res. 92, 4853 (1987); T. Katsura and E. Ito, ibid. 94, 15663 (1989); M. Akaogi and E. Ito, ibid., p. 15671.
9. E. Ito and E. Takahashi, J. Geophys. Res. 94, 10637 (1989).
10. E. Ito, M. Akaogi, T. Topor, A. Navrotsky, Science 249, 1275 (1990).
11. H. Morishima et al., ibid. 265, 1202 (1994).
12. T. Kato et al., J. Geophys. Res. 100, 20475 (1995); T. Kato et al., Spec. Issue Rev. High Press. Sci. Technol. 6, 718 (1997).
13. T. Kato et al., J. Geophys. Res. 100, 20475 (1995); T. Kato et al., Spec. Issue Rev. High Press. Sci. Technol. 6, 718 (1997).
14. W. Utsumi et al., Spec. Issue Rev. High Press. Sci. Technol. 6, 512 (1997).
15. We used sintered magnesia as a pressure medium and pyrophyllite as the gasket material. Tungsten carbide cubes with truncated edge length (TEL) of 3.0 mm were used as the second-stage anvils. The heater was made of twin sheets of cemented TiC + diamond powders, and the temperature was measured by means of a W97Re3-W75Re25 thermocouple without correction of the effect of pressure on the thermoelectromotive force. The fluctuation of temperature was within ±0.5% throughout the present runs up to 1800°C. The temperature difference between the central and edge parts of the disk sample may be of the order of ±1 to 2% of the nominal temperature, as estimated by the textural observations of the run products and the melting behavior of Au in subsequent experiments. Further details of the cell design and experimental techniques will be given elsewhere (N. Nishiyama et al., in preparation).
16. An equation of state proposed by O. L. Anderson, D. G. Isaak, and S. Yamamoto [J. Appl. Phys. 65, 1534 (1989)] was used to calculate the pressure from the unit cell volume of Au. The consistency of this pressure scale with the established NaCI scale [D. L. Decker, J. Appl. Phys. 42, 3239 (1971)] was confirmed by N. Funamori et al. [J. Geophys. Res. 101, 8257 (1996)], which demonstrated that the differences of the pressures based on these two scales are within 0.2 to 0.4 GPa at temperatures 1000° to 1600°C and at pressures near 25 GPa.
17. An equation of state proposed by O. L. Anderson, D. G. Isaak, and S. Yamamoto [J. Appl. Phys. 65, 1534 (1989)] was used to calculate the pressure from the unit cell volume of Au. The consistency of this pressure scale with the established NaCI scale [D. L. Decker, J. Appl. Phys. 42, 3239 (1971)] was confirmed by N. Funamori et al. [J. Geophys. Res. 101, 8257 (1996)], which demonstrated that the differences of the pressures based on these two scales are within 0.2 to 0.4 GPa at temperatures 1000° to 1600°C and at pressures near 25 GPa.
18. An equation of state proposed by O. L. Anderson, D. G. Isaak, and S. Yamamoto [J. Appl. Phys. 65, 1534 (1989)] was used to calculate the pressure from the unit cell volume of Au. The consistency of this pressure scale with the established NaCI scale [D. L. Decker, J. Appl. Phys. 42, 3239 (1971)] was confirmed by N. Funamori et al. [J. Geophys. Res. 101, 8257 (1996)], which demonstrated that the differences of the pressures based on these two scales are within 0.2 to 0.4 GPa at temperatures 1000° to 1600°C and at pressures near 25 GPa.
19. These pressures at room temperature may be over-estimated by 2 to 3 GPa because of the effect of deviatoric stress within the sample charge, which would approach zero upon heating above 600° to 800°C [D. J. Weidner et al., in High-Pressure Research: Application to Earth and Planetary Sciences, Y. Syono and M. H. Manghnani, Eds. (Terrapub/ American Geophysical Union, Tokyo/Washington, DC, 1992), pp. 13-17].
20. White x-rays from the synchrotron radiation available at a bending magnet beamline (BL04B1 ) at SPring-8 T were directed to the sample near the hot junction of the thermocouple by horizontal (100 μm) and vertical (200 μm) slits, and the diffracted beam, collimated by a 100-μm horizontal slit, was detected with a Ge solid-state detector. We used a horizontally rotating goniometer, 2 θ being fixed at 5.0°, which was calibrated with the major four to five diffraction peaks ot Au at the ambient pressure.
21. I. Martinez, Y. Wang, F. Guyot, R. C. Liebermann, J. C. Doukhan, J. Geophys. Res. 102, 5256 (1997); Y. Wang, I. Martinez, F. Guyot, R. C. Liebermann, Science 275, 510 (1997).
22. I. Martinez, Y. Wang, F. Guyot, R. C. Liebermann, J. C. Doukhan, J. Geophys. Res. 102, 5256 (1997); Y. Wang, I. Martinez, F. Guyot, R. C. Liebermann, Science 275, 510 (1997).
23. J. Zhang, B. Li, W. Utsumi, R. C. Liebermann, Phys. Chem. Miner. 23, 1 (1996).
24. E. Ito and H. Sato, Nature 351, 140 (1991); D. Yamazaki, T. Kato, E. Ohtani, M. Toriumi, Science 274, 2052 (1996).
25. E. Ito and H. Sato, Nature 351, 140 (1991); D. Yamazaki, T. Kato, E. Ohtani, M. Toriumi, Science 274, 2052 (1996).
26. E. Ito and T. Katsura, Geophys. Res. Lett. 16, 425 (1989); J. J. Brown and T. J. Shankland, Geophys J. R. Astron. Soc. 66, 579 (1981).
27. E. Ito and T. Katsura, Geophys. Res. Lett. 16, 425 (1989); J. J. Brown and T. J. Shankland, Geophys J. R. Astron. Soc. 66, 579 (1981).
28. P. M. Shearer and T. G. Masters, Nature 355, 791 (1992).
29. 3 perovskite and MgO periclase according to N. Funamori et al. [J. Geophys. Res. 101, 8257 (1996)]. These resuits were generally consistent with those based OP the Au scale, but yielded somewhat higher pressures. Nevertheless, the discrepancy was on the order of ∼ 0.5 GPa and does not affect the present conclusion.
30. R. C. Liebermann et al., Spec. Issue Rev. High Press. Sci. Technol. 6, 61 (1997).
31. We acknowledge N. Kubo for technical assistance and O. Shimomura for encouragement and useful comments. The x-ray experiments were carried out. at SPring-8 (proposal No. 1997B0049-NOM-np).