Oriented grain growth and modification of ‘frozen anisotropy’ in the lithospheric mantle

Yuval Boneh, David Wallis, Lars N. Hansen, Mike J. Krawczynski, Philip Skemer

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

Seismic anisotropy throughout the oceanic lithosphere is often assumed to be generated by fossilized texture formed during deformation at asthenospheric temperatures close to the ridge. Here we investigate the effect of high-temperature and high-pressure static annealing on the texture of previously deformed olivine aggregates to simulate residence of deformed peridotite in the lithosphere. Our experiments indicate that the orientation and magnitude of crystallographic preferred orientation (CPO) will evolve due to the preferential growth of grains with low dislocation densities. These observations suggest that texture and stored elastic strain energy promote a style of grain growth that modifies the CPO of a deformed aggregate. We demonstrate that these microstructural changes alter the orientation distributions and magnitudes of seismic wave velocities and anisotropy. Therefore, static annealing may complicate the inference of past deformation kinematics from seismic anisotropy in the lithosphere.

Original languageEnglish (US)
Pages (from-to)368-374
Number of pages7
JournalEarth and Planetary Science Letters
Volume474
DOIs
StatePublished - Sep 15 2017
Externally publishedYes

Bibliographical note

Funding Information:
The authors thanks Gayle Gleason for enriching discussions and to Manuele Faccenda and anonymous reviewer for their constructive comments. This research is supported by NSF EAR-1131985 (to PS), with additional support from the Institute of Materials Science and Engineering at Washington University in St. Louis. DW and LNH acknowledge support from the Natural Environment Research Council Grant NE/M000966/1.

Publisher Copyright:
© 2017 The Authors

Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.

Keywords

  • crystallographic preferred orientation
  • grain growth
  • mantle lithosphere
  • olivine
  • seismic anisotropy

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