Ultrasonic Observations of Elasticity Changes Across Phase Transformations in MgSiO3 Pyroxenes
Using ultrasonic interferometry in conjunction with synchrotron X-radiation techniques in a high-pressure, multi-anvil apparatus, the elastic behavior of MgSiO{sub 3} pyroxene has been continuously monitored as the specimens undergo phase transformations from the orthoenstatite (OEN) to the high-pressure clinoenstatite phase (HP-CEN) and from HP-CEN to the low-pressure clinoenstatite phase (LP-CEN). In the former case, elastic softening and amplitude attenuation is observed for both compresssional (P) and shear (S) waves when the pressure exceeds 9 GPa at room temperature, which we suggest is associated with a transition to a metastable phase intermediate between OEN and HP-CEN. In the latter case, both P and S wave velocities decrease rapidly as the back-transformation from HP-CEN to LP-CEN occurs on decrease of pressure below 4 GPa at room temperature; this is accompanied by an increase in attenuation of the P waves in the specimen, but not the S waves.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source
- Sponsoring Organization:
- Doe - Office Of Science
- DOE Contract Number:
- DE-AC02-98CH10886
- OSTI ID:
- 930098
- Report Number(s):
- BNL-80736-2008-JA; JPCSAW; TRN: US0806704
- Journal Information:
- Journal of Physics and Chemistry of Solids, Vol. 67, Issue 39701; ISSN 0022-3697
- Country of Publication:
- United States
- Language:
- English
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