Iron Partitioning in Earth's Mantle: Toward a Deep Lower Mantle Discontinuity

J. Badro; Guillaume Fiquet; François Guyot; Jean-Pascal Rueff; Viktor V. Struzhkin; György Vanko; Giulio Monaco

doi:10.1126/science.1081311

Journal articles

Iron Partitioning in Earth's Mantle: Toward a Deep Lower Mantle Discontinuity

J. Badro ^{1, 2} Guillaume Fiquet ^{1, 2} François Guyot ³ Jean-Pascal Rueff ⁴ Viktor V. Struzhkin ⁵ György Vanko ⁶ Giulio Monaco ⁶

1 IMPMC - Institut de minéralogie et de physique des milieux condensés

2 IPGP - Institut de Physique du Globe de Paris

3 Laboratoire de Mine ́ralogie–Cristallographie de Paris,Universite ́ Paris VI, Universite ́ Paris 7, CNRS, IPGP, 4place Jussieu, F-75252 Paris Cedex 05, France.

4 LCPMR - Laboratoire de Chimie Physique - Matière et Rayonnement

5 Geophysical Laboratory [Carnegie Institution]

6 European Synchrotron Radiation Facility(ESRF), B.P. 220 F-38043 Grenoble CEDEX, France

Abstract : We measured the spin state of iron in ferropericlase (Mg0.83Fe0.17)O at high pressure and found a high-spin to low-spin transition occurring in the 60- to 70-gigapascal pressure range, corresponding to depths of 2000 kilometers in Earth's lower mantle. This transition implies that the partition coefficient of iron between ferropericlase and magnesium silicate perovskite, the two main constituents of the lower mantle, may increase by several orders of magnitude, depleting the perovskite phase of its iron. The lower mantle may then be composed of two different layers. The upper layer would consist of a phase mixture with about equal partitioning of iron between magnesium silicate perovskite and ferropericlase, whereas the lower layer would consist of almost iron-free perovskite and iron-rich ferropericlase. This strati. cation is likely to have profound implications for the transport properties of Earth's lowermost mantle

Keywords : KeyWords Plus:X-RAY-EMISSION HIGH-PRESSURE SILICATE PEROVSKITE SPECTROSCOPY TRANSITION SPIN TEMPERATURE DYNAMICS (MG FE)SIO3-PEROVSKITE MAGNESIOWUSTITE

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Journal articles

Domain :

Sciences of the Universe [physics]

Sciences of the Universe [physics] / Earth Sciences

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Iron Partitioning in Earth's Mantle: Toward a Deep Lower Mantle Discontinuity

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Iron Partitioning in Earth's Mantle: Toward a Deep Lower Mantle Discontinuity

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