Shear deformation of bridgmanite and magnesiowüstite aggregates at lower mantle conditions

Jennifer Girard, George Amulele, Robert Farla, Anwar Mohiuddin, Shun-ichiro Karato

    Research output: Contribution to journalArticlepeer-review

    118 Citations (Scopus)


    Rheological properties of the lower mantle have strong influence on the dynamics and evolution of Earth. By using the improved methods of quantitative deformation experiments at high pressures and temperatures, we deformed a mixture of bridgmanite and magnesiowüstite under the shallow lower mantle conditions. We conducted experiments up to about 100% strain at a strain rate of about 3 × 10⁻⁵ second⁻¹. We found that bridgmanite is substantially stronger than magnesiowüstite and that magnesiowüstite largely accommodates the strain. Our results suggest that strain weakening and resultant shear localization likely occur in the lower mantle. This would explain the preservation of long-lived geochemical reservoirs and the lack of seismic anisotropy in the majority of the lower mantle except the boundary layers.
    Original languageEnglish
    Pages (from-to)144-147
    Number of pages4
    Issue number6269
    Publication statusPublished - 8 Jan 2016


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