title: Iron spin transition in Earth's mantle.
abstract: High-pressure Mössbauer spectroscopy on several compositions across the (Mg,Fe)O magnesiowüstite solid solution confirms that ferrous iron (Fe(2+)) undergoes a high-spin to low-spin transition at pressures and for compositions relevant to the bulk of the Earth's mantle. High-resolution x-ray diffraction measurements document a volume change of 4-5% across the pressure-induced spin transition, which is thus expected to cause seismological anomalies in the lower mantle. The spin transition can lead to dissociation of Fe-bearing phases such as magnesiowüstite, and it reveals an unexpected richness in mineral properties and phase equilibria for the Earth's deep interior.
authors.affiliation: Department of Earth and Planetary Science, University of California, Berkeley, 94720, USA.
authors.forename: S
authors.initials: S
authors.lastname: Speziale
authors.forename: A
authors.initials: A
authors.lastname: Milner
authors.forename: V E
authors.initials: VE
authors.lastname: Lee
authors.forename: S M
authors.initials: SM
authors.lastname: Clark
authors.forename: M P
authors.initials: MP
authors.lastname: Pasternak
authors.forename: R
authors.initials: R
authors.lastname: Jeanloz