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In-situ measurement of texture development rate in CaIrO3 post-perovskite

Hunt, SA; Walker, AM; Mariani, E; (2016) In-situ measurement of texture development rate in CaIrO3 post-perovskite. Physics of the Earth and Planetary Interiors , 257 pp. 91-104. 10.1016/j.pepi.2016.05.007. Green open access

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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.

Type: Article
Title: In-situ measurement of texture development rate in CaIrO3 post-perovskite
Open access status: An open access version is available from UCL Discovery
DOI: 10.1016/j.pepi.2016.05.007
Publisher version: http://dx.doi.org/10.1016/j.pepi.2016.05.007
Language: English
Additional information: © 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Earth Sciences
URI: https://discovery.ucl.ac.uk/id/eprint/1508343
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