Compressional Behavior and Elastic Properties of Sintered Polycrystalline Fe-Al-Bearing Bridgmanite

POSTER

Abstract

Bridgmanite, the most abundant mineral in Earth’s lower mantle, can incorporate iron and aluminum into its crystal structure, thereby altering its physical and chemical properties under extreme conditions. In this study, we investigated pre-synthesized sintered polycrystalline Fe-Al-bearing bridgmanite samples using high‐pressure diamond anvil cell (DAC) experiments coupled with synchrotron X-ray diffraction to assess their compressional behavior up to 96 GPa. Our measurements of the pressure–volume (PV) relationships demonstrate that the compressibility is primarily influenced by sample composition. The bridgmanite sample (Mg0.68Fe0.32)(Si0.70Al0.30)O3 exhibits larger unit-cell volumes and different compression trends compared to the (Mg0.83Fe0.17)(Si0.91Al0.09)O3 sample. While various pressure-transmitting media (He, Ne, Ar) were tested for the (Mg0.68Fe0.32)(Si0.70Al0.30)O3 sample, this effect was secondary to compositional differences. By fitting the PV data to third‐order Birch–Murnaghan equations of state, we constrain the bulk moduli and their pressure derivatives for both compositions, providing a quantitative understandings into how Fe and Al substitutions modify bridgmanite’s elastic properties. Additional lattice-parameter analyses also reveal the anisotropic behavior under high-pressure conditions, offering a more detailed understanding of the structure–property relationships in Fe-Al-bearing bridgmanite at lower-mantle pressures.

*Funded by the European Research Council

Presenters

  • Britany Kulka

    • School of Earth and Space Exploration, Arizona State University, Tempe, AZ, US
    • Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK.
    • Department of Earth Sciences, University of Oxford, S Parks Rd, Oxford OX1 3AN, UK
    • University of Oxford

Authors

  • Britany Kulka

    • School of Earth and Space Exploration, Arizona State University, Tempe, AZ, US
    • Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK.
    • Department of Earth Sciences, University of Oxford, S Parks Rd, Oxford OX1 3AN, UK
    • University of Oxford

  • Egor Komets

    • Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, UK.

  • Estelle Ledoux

    • Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK.

  • Jonathan Dolinschi

    • Department of Earth Sciences, University of Oxford, S Parks Rd, Oxford OX1 3AN, UK
    • University of Oxford

  • Hauke Marquardt

    • Department of Earth Sciences, University of Oxford, S Parks Rd, Oxford OX1 3AN, UK