In-situ measurement of texture development rate in CaIrO 3 post-perovskite
The rate of crystallographic preferred orientation (CPO) development during deformation of post-perovskite is crucial in interpreting seismic anisotropy in the lowermost mantle but the stability field of MgSiO3 post-perovskite prevents high-strain deformation experiments being performed on it. Therefore, to constrain the rate of CPO development in post-perovskite, we deformed CaIrO3, a low-pressure analogue of MgSiO3 post-perovskite, in simple shear at 3.2 GPa and 400 °C to a shear strain (γ) of 0.81. From X-ray diffraction patterns acquired during deformation, we invert for CPO as a function of strain. By comparing the CPO that develops with visco-plastic self-consistent (VPSC) models we constrain the critical resolved shear stresses (CRSS) of the non-primary slip-systems in CaIrO3 to be of order 6 times stronger than the primary [100] (010) slip system. This value is significantly less than has been assumed by previous studies and if applicable to MgSiO3 implies that seismic anisotropy in the D" layer develops slower than has previously been assumed.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- DOE Contract Number:
- SC00112704
- OSTI ID:
- 1354242
- Report Number(s):
- BNL-112758-2016-JA¿¿¿
- Journal Information:
- Physics of the Earth and Planetary Interiors, Vol. 257, Issue C; ISSN 0031-9201
- Publisher:
- Elsevier
- Country of Publication:
- United States
- Language:
- English
Similar Records
Seismic anisotropy, dominant slip systems and phase transitions in the lowermost mantle
The enigma of post-perovskite anisotropy: deformation versus transformation textures