Effect of the incorporation of FeAlO3 into MgSiO3 perovskite on the post-perovskite transition

摘要

Effect of the incorporation of FeAlO3 into MgSiO3 perovskite on post-perovskite transition was investigated in Mg0.85Fe0.15Al0.15Si0.85O3 on the basis of high pressure and temperature in-situ X-ray diffraction experiments using a laser heated diamond anvil cell. Results demonstrate that single perovskite is stable up to 143 GPa and 2500 K and perovskite and post-perovskite coexist at 157- 162 GPa and 1600 - 2500 K for the pressure scales by Tsuchiya ( 2003). Post-perovskite formed as single phase at 176 - 178 GPa and 1600 - 2600 K. The post-perovskite transition pressure in Mg0.85Fe0.15Al0.15Si0.85O3 was much higher than that in MgSiO3. The present experimental study indicates that the incorporation of FeAlO3 component expands the stability region of perovskite toward high pressure. The FeAlO3 concentration may strongly influence the thickness of the D '' layer at the lowermost of the lower mantle.