Physics and Chemistry of Minerals

, Volume 40, Issue 2, pp 107–113

Iron partitioning in pyrolitic lower mantle

Authors

    • Department of Earth and Planetary SciencesTokyo Institute of Technology
    • Bayerisches GeoinstitutUniversität Bayreuth
  • Kei Hirose
    • Department of Earth and Planetary SciencesTokyo Institute of Technology
Original Paper

DOI: 10.1007/s00269-012-0551-7

Cite this article as:
Sinmyo, R. & Hirose, K. Phys Chem Minerals (2013) 40: 107. doi:10.1007/s00269-012-0551-7

Abstract

The partitioning of iron between Mg-rich perovskite (Pv) and ferropericlase (Fp) was investigated for a pyrolitic bulk composition over a wide range of simulated lower-mantle pressures and temperatures from 28 to 114 GPa and from 1,900 to 2,300 K, in a laser-heated diamond anvil cell (DAC). The recovered DAC samples are chemically homogeneous, indicating a relatively small temperature gradient during laser heating. The chemical compositions of coexisting Pv, Fp, and Ca-rich perovskite (CaPv) were determined by energy-dispersive X-ray spectroscopy (EDS) using an EDS instrument attached to a transmission electron microscope. Our results demonstrate that at pressures above 90 GPa, Pv becomes more Fe-rich with increasing pressure, which is likely due to the effects of high-spin to low-spin crossover of Fe3+ in Pv. We highlight that such a change in Fe–Mg partitioning between Pv and Fp should have a strong influence on the physical properties of the deep lower mantle.

Keywords

Lower mantle Iron partitioning Perovskite Ferropericlase Diamond anvil cell Transmission electron microscope

Copyright information

© Springer-Verlag Berlin Heidelberg 2012