Solving Controversies on the Iron Phase Diagram Under High Pressure

Research output: Contribution to journalJournal article – Annual report year: 2018Researchpeer-review

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  • Author: Morard, Guillaume

    Museum National d'Histoire Naturelle

  • Author: Boccato, Silvia

    European Synchrotron Radiation Facility

  • Author: Rosa, Angelika D.

    European Synchrotron Radiation Facility

  • Author: Anzellini, Simone

    Diamond Light Source

  • Author: Miozzi, Francesca

    Museum National d'Histoire Naturelle

  • Author: Henry, Laura

    European Synchrotron Radiation Facility

  • Author: Garbarino, Gaston

    European Synchrotron Radiation Facility

  • Author: Mezouar, Mohamed

    European Synchrotron Radiation Facility

  • Author: Harmand, Marion

    Museum National d'Histoire Naturelle

  • Author: Guyot, François

    Museum National d'Histoire Naturelle

  • Author: Boulard, Eglantine

    Museum National d'Histoire Naturelle

  • Author: Kantor, Innokenty

    Neutrons and X-rays for Materials Physics, Department of Physics, Technical University of Denmark, Fysikvej, 2800, Kgs. Lyngby, Denmark

  • Author: Irifune, Tetsuo

    Ehime University

  • Author: Torchio, Raffaella

    European Synchrotron Radiation Facility

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As the main constituent of planetary cores, pure iron phase diagram under high pressure and temperature is of fundamental importance in geophysics and planetary science. However, previously reported iron-melting curves show large discrepancies (up to 1000 K at the Earth's core–mantle boundary, 136 GPa), resulting in persisting high uncertainties on the solid-liquid phase boundary. Here we unambiguously show that the observed differences commonly attributed to the nature of the used melting diagnostic are due to a carbon contamination of the sample as well as pressure overestimation at high temperature. The high melting temperature of pure iron under core-mantle boundary (4250 ± 250 K), here determined by X-ray absorption experiments at the Fe K-edge, indicates that volatile light elements such as sulfur, carbon, or hydrogen are required to lower the crystallization temperature of the Earth's liquid outer core in order to prevent extended melting of the surrounding silicate mantle.

Original languageEnglish
JournalGeophysical Research Letters
Volume45
Issue number20
Pages (from-to)11,074-11,082
Number of pages9
ISSN0094-8276
DOIs
Publication statusPublished - 2018
CitationsWeb of Science® Times Cited: No match on DOI

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