TY - JOUR
T1 - Phase transition in CaSiO3 perovskite
AU - Komabayashi, T.
AU - Hirose, K.
AU - Dubrovinsky, L.S.
AU - Sata, N.
AU - Ohishi, Y.
PY - 2007/8/30
Y1 - 2007/8/30
N2 - A phase transition in pure CaSiO3 perovskite was investigated at 27 to 72 GPa and 300 to 819 K by in-situ X-ray diffraction experiments in an externally-heated diamond-anvil cell. The results show that CaSiO3 perovskite takes a tetragonal form at 300 K and undergoes phase transition to a cubic structure above 490-580 K in a pressure range studied here. The transition boundary is strongly temperature-dependent with a slightly positive dT / dP slope of 1.1 (± 1.3) K/GPa. It is known that the transition temperature depends on AlO content dissolved in CaSiO3 perovskite [Kurashina et al., Phys. Earth Planet. Inter. 145 (2004) 67-74]. The phase transition in CaSiO3(+ 3 wt.% AlO) perovskite therefore could occur in a cold subducted mid-oceanic ridge basalt (MORB) crust at about 1200 K in the upper- to mid-lower mantle. This phase transition is possibly ferroelastic-type and may cause large seismic anomalies in a wide depth range.
AB - A phase transition in pure CaSiO3 perovskite was investigated at 27 to 72 GPa and 300 to 819 K by in-situ X-ray diffraction experiments in an externally-heated diamond-anvil cell. The results show that CaSiO3 perovskite takes a tetragonal form at 300 K and undergoes phase transition to a cubic structure above 490-580 K in a pressure range studied here. The transition boundary is strongly temperature-dependent with a slightly positive dT / dP slope of 1.1 (± 1.3) K/GPa. It is known that the transition temperature depends on AlO content dissolved in CaSiO3 perovskite [Kurashina et al., Phys. Earth Planet. Inter. 145 (2004) 67-74]. The phase transition in CaSiO3(+ 3 wt.% AlO) perovskite therefore could occur in a cold subducted mid-oceanic ridge basalt (MORB) crust at about 1200 K in the upper- to mid-lower mantle. This phase transition is possibly ferroelastic-type and may cause large seismic anomalies in a wide depth range.
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-34447546594&partnerID=8YFLogxK
U2 - 10.1016/j.epsl.2007.06.015
DO - 10.1016/j.epsl.2007.06.015
M3 - Article
AN - SCOPUS:34447546594
SN - 0012-821X
VL - 260
SP - 564
EP - 569
JO - Earth and Planetary Science Letters
JF - Earth and Planetary Science Letters
IS - 3-4
ER -