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Transformation textures in post-perovskite: Understanding mantle flow in the D '' layer of the Earth

Walte, NP; Heidelbach, F; Miyajima, N; Frost, DJ; Rubie, DC; Dobson, DP; (2009) Transformation textures in post-perovskite: Understanding mantle flow in the D '' layer of the Earth. Geophysical Research Letters , 36 , Article L04302. 10.1029/2008GL036840. Green open access

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Abstract

Deformation and texture formation in (Mg, Fe)SiO3 post perovskite (ppv) is a potential explanation for the strong seismic anisotropy that is found in the D '' layer of the Earth. However, different experimental approaches have resulted in different lattice preferred orientations (LPO) in deformed ppv that have led to ambiguity in the interpretation of deformation in the lowermost mantle. Here, we show that deformation of the analogue substance CaIrO3 during a phase transformation from perovskite to ppv leads to a transformation texture that differs from the CaIrO3 ppv deformation texture but resembles the results from ppv deformation experiments in diamond anvil cells. Assuming material spreading parallel to the core-mantle boundary, our results predict a widespread shear wave splitting with fast horizontal S-waves, which is compatible with seismic studies. Downwelling material that undergoes a phase transformation may develop a transformation texture that would locally result in vertically polarized fast S-waves. Citation: Walte, N. P., F. Heidelbach, N. Miyajima, D. J. Frost, D. C. Rubie, and D. P. Dobson (2009), Transformation textures in post-perovskite: Understanding mantle flow in the D '' layer of the Earth, Geophys. Res. Lett., 36, L04302, doi: 10.1029/2008GL036840.

Type: Article
Title: Transformation textures in post-perovskite: Understanding mantle flow in the D '' layer of the Earth
Open access status: An open access version is available from UCL Discovery
DOI: 10.1029/2008GL036840
Publisher version: http://dx.doi.org/10.1029/2008GL036840
Language: English
Additional information: Copyright 2009 by the American Geophysical Union
Keywords: Seismic anisotropy, Phase-transition, Lowermost mantle, Deformation, MgSiO3, GPa, 1st-principles, Wadsleyite, Pressures, Boundary
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/168534
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