TY - JOUR
T1 - New High-Pressure Forms of Al2SiO5
AU - Zhou, Y.
AU - Irifune, T.
AU - Ohfuji, H.
AU - Kuribayashi, T.
N1 - Funding Information:
The authors declare no competing financial interests. All the data are available and accessible in the supporting information. This work is funded by JSPS Grant-in-Aid for Scientific Research (25220712 and 15H05829). The authors thank N. Uchiyama, Y. Kojima, S. Ohnishi, and N. Asano for technical assistance in the structural analysis.
Publisher Copyright:
©2018. American Geophysical Union. All Rights Reserved.
PY - 2018/8/28
Y1 - 2018/8/28
N2 - Phase relations of Al2SiO5 have been studied by multianvil experiments at pressures of 13–23 GPa and temperatures of 2000–2900 K. Al2SiO5 kyanite was found to transform into two new high-pressure forms of Al2SiO5 (kyanite II and III) at temperatures exceeding 2300–2500 K and pressures of 14–23 GPa: The first phase transition occurs near 14 GPa, and the second occurs near 17 GPa. The new Al2SiO5 phases have triclinic and monoclinic crystal symmetries with zero-pressure densities of 3.876(2) and 3.982(1) g/cm3, respectively, which are significantly denser than kyanite (ρ0 = 3.666 g/cm3) but less dense than the isochemical mixture of Al2O3 corundum and SiO2 stishovite (ρ0 = 4.036 g/cm3). The exceptionally high stability temperatures of the new Al2SiO5 phases suggest that they are unlikely to form in the present mantle but may be found in some impact craters and shocked meteorites and act as important indicators of pressure and temperature for the shock events.
AB - Phase relations of Al2SiO5 have been studied by multianvil experiments at pressures of 13–23 GPa and temperatures of 2000–2900 K. Al2SiO5 kyanite was found to transform into two new high-pressure forms of Al2SiO5 (kyanite II and III) at temperatures exceeding 2300–2500 K and pressures of 14–23 GPa: The first phase transition occurs near 14 GPa, and the second occurs near 17 GPa. The new Al2SiO5 phases have triclinic and monoclinic crystal symmetries with zero-pressure densities of 3.876(2) and 3.982(1) g/cm3, respectively, which are significantly denser than kyanite (ρ0 = 3.666 g/cm3) but less dense than the isochemical mixture of Al2O3 corundum and SiO2 stishovite (ρ0 = 4.036 g/cm3). The exceptionally high stability temperatures of the new Al2SiO5 phases suggest that they are unlikely to form in the present mantle but may be found in some impact craters and shocked meteorites and act as important indicators of pressure and temperature for the shock events.
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U2 - 10.1029/2018GL078960
DO - 10.1029/2018GL078960
M3 - Article
AN - SCOPUS:85053193498
SN - 0094-8276
VL - 45
SP - 8167
EP - 8172
JO - Geophysical Research Letters
JF - Geophysical Research Letters
IS - 16
ER -