HR: 0830h
AN: T11C-0401    [PDF]
TI: Stability of Perovskite under Lower Mantle Pressure and Temperature Conditions
AU: * Zhang, L
EM: miazl1980@hotmail.com
AF: Institute of Physics, Southwest Jiaotong University,, No.111,Nort section, second circle Rd., Chengdu, 610031 China
AU: Gong, Z
EM: z.gong@gl.ciw.edu
AF: Institute of Physics, Southwest Jiaotong University,, No.111,Nort section, second circle Rd., Chengdu, 610031 China
AU: Gong, Z
EM: z.gong@gl.ciw.edu
AF: Geophycical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch, NW,, Washington, DC 20015 United States
AU: Fei, Y
EM: fei@gl.ciw.edu
AF: Geophycical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch, NW,, Washington, DC 20015 United States
AU: Jing, F
EM: jingfq@caep.ac.cn
AF: Laboratory for Shock Wave and Detonation Physics Research, Institute of Fluid Physics, P.O.Box 919, Mianyang, 621900 China
AB: Shock recovery experiments of (Mg$_{0.92}$, Fe$_{0.08}$)SiO$_{3}$ enstatite were conducted at pressures between 60 and 120GPa with the corresponding temperatures of 1600-3000K. X-ray diffraction (XRD) and infrared absorption spectra (IR) analysis on recovered samples indicates that the main phase of the recovered samples is not perovskite, but similar to enstatite. There is no evidence for presence of oxides SiO$_{2}$ and (Mg$_{0.92}$, Fe$_{0.08}$)O in the recovered samples. The XRD data show that some diffraction peaks of the recovered samples cannot be matched with the diffraction pattern of the original sample. These peaks are more obvious with increasing pressure. The shock recovery experiments were performed in the stability field of perovskite. The shocked sample is expected to be of the perovskite structure, supported by the observed Hugoniot equation of state of perovskite. The non-perovskite phase in the recovered sample is likely resulted from a retrogressive transformation of the shocked samples during the unloading process. It is evident that the high-pressure phase did not undergo a chemical decomposition reaction of (Mg$_{0.92}$, Fe$_{0.08}$)SiO$_{3}$ to oxides SiO$_{2}$ and (Mg$_{0.92}$, Fe$_{0.08}$)O during the shock compression because no SiO$_{2}$ and (Mg$_{0.92}$, Fe$_{0.08}$)O oxides were found in the recovered samples. The observed extra diffraction in the recovered sample may be caused by crystal distortion. Further characterization of the recovered sample by TEM may shine some light on the nature of the retrogressive transformation of the shocked samples.
DE: 3919 Equations of state
DE: 3924 High-pressure behavior
DE: 3939 Physical thermodynamics
DE: 3944 Shock wave experiments
DE: 8124 Earth's interior--composition and state (old 8105)
SC: Tectonophysics [T]
MN: 2003 Fall Meeting