<i>In</i>-<i>situ</i> measurement of texture development rate in CaIrO<sub>3</sub> post-perovskite



Hunt, Simon A, Walker, Andrew M and Mariani, Elisabetta ORCID: 0000-0002-0585-5265
(2016) <i>In</i>-<i>situ</i> measurement of texture development rate in CaIrO<sub>3</sub> post-perovskite. PHYSICS OF THE EARTH AND PLANETARY INTERIORS, 257. pp. 91-104.

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Abstract

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.

Item Type: Article
Uncontrolled Keywords: Electron back-scatter diffraction (EBSD), Orientation distribution function (ODF), Lattice preferred orientation (LPO), Inverse pole figure, D '' layer
Depositing User: Symplectic Admin
Date Deposited: 21 May 2019 08:34
Last Modified: 05 Oct 2023 09:26
DOI: 10.1016/j.pepi.2016.05.007
Open Access URL: http://authors.elsevier.com/sd/article/S0031920116...
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URI: https://livrepository.liverpool.ac.uk/id/eprint/3038206

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