High-pressure and high-temperature phase relations in CaSiO3 and CaMgSi2O6 and elasticity of perovskite-type CaSiO3

1989 ◽  
Vol 54 (3-4) ◽  
pp. 370-377 ◽  
Author(s):  
Hiroshi Tamai ◽  
Takehiko Yagi
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
High Temperature Phase ◽  
Phase Relations ◽  
Temperature Phase ◽  
Perovskite Type

scholarly journals High-Pressure and High-Temperature Phase Transitions in Fe2TiO4 and Mg2TiO4 with Implications for Titanomagnetite Inclusions in Superdeep Diamonds

Minerals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 614 ◽  
Author(s):  
Akaogi ◽  
Tajima ◽  
Okano ◽  
Kojitani
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
High Temperature ◽  
Spin Transition ◽  
Calcium Titanate ◽  
High Temperature Phase ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
Spinel Type ◽  
Perovskite Type

Phase transitions of Mg2TiO4 and Fe2TiO4 were examined up to 28 GPa and 1600 °C using a multianvil apparatus. The quenched samples were examined by powder X-ray diffraction. With increasing pressure at high temperature, spinel-type Mg2TiO4 decomposes into MgO and ilmenite-type MgTiO3 which further transforms to perovskite-type MgTiO3. At 21 GPa, the assemblage of MgTiO3 perovskite + MgO changes to 2MgO + TiO2 with baddeleyite (or orthorhombic I)-type structure. Fe2TiO4 undergoes transitions similar to Mg2TiO4 with pressure: spinel-type Fe2TiO4 dissociates into FeO and ilmenite-type FeTiO3 which transforms to perovskite-type FeTiO3. Both of MgTiO3 and FeTiO3 perovskites change to LiNbO3-type phases on release of pressure. In Fe2TiO4, however, perovskite-type FeTiO3 and FeO combine into calcium titanate-type Fe2TiO4 at 15 GPa. The formation of calcium titanate-type Fe2TiO4 at high pressure may be explained by effects of crystal field stabilization and high spin–low spin transition in Fe2+ in the octahedral sites of calcium titanate-type Fe2TiO4. It is inferred from the determined phase relations that some of Fe2TiO4-rich titanomagnetite inclusions in diamonds recently found in São Luiz, Juina, Brazil, may be originally calcium titanate-type Fe2TiO4 at pressure above 15 GPa in the transition zone or lower mantle and transformed to spinel-type in the upper mantle conditions.

High-pressure and high-temperature phase relations in diopside CaMgSi2O6

1997 ◽  
Vol 104 (4) ◽  
pp. 363-370 ◽  
Author(s):  
Katsuya Oguri ◽  
Nobumasa Funamori ◽  
Fumiko Sakai ◽  
Tadashi Kondo ◽  
Takeyuki Uchida ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
High Temperature Phase ◽  
Phase Relations ◽  
Temperature Phase

scholarly journals High-pressure high-temperature phase relations in MgAl2O4

2010 ◽  
Vol 215 ◽  
pp. 012098 ◽  
Author(s):  
H Kojitani ◽  
A Enomoto ◽  
S Tsukamoto ◽  
M Akaogi ◽  
H Miura ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
High Temperature Phase ◽  
Phase Relations ◽  
Temperature Phase ◽  
High Pressure High Temperature

High-pressure high-temperature phase relations in FeTiO3 up to 35 GPa and 1600 °C

2016 ◽  
Vol 44 (1) ◽  
pp. 63-73 ◽  
Author(s):  
M. Akaogi ◽  
K. Abe ◽  
H. Yusa ◽  
T. Ishii ◽  
T. Tajima ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
High Temperature Phase ◽  
Phase Relations ◽  
Temperature Phase ◽  
High Pressure High Temperature
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