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Effect of light elements on the sound velocities in solid iron: Implications for the composition of Earth's core

Research output: Contribution to journalArticle

  • James Badro
  • Guillaume Fiquet
  • Francois Guyot
  • Eugene Gregoryanz
  • Florent Occelli
  • Daniele Antonangeli
  • Matteo d'Astuto

Related Edinburgh Organisations

Original languageEnglish
Pages (from-to)233-238
Number of pages6
JournalEarth and Planetary Science Letters
Issue number1-2
Publication statusPublished - 15 Feb 2007


We measured compressional sound velocities in light element alloys of iron (FeO, FeSi, FeS, and FeS2) at high-pressure by inelastic X-ray scattering. This dataset provides new mineralogical constraints on the composition of Earth's core, and completes the previous sets formed by the pressure-density systematics for these compounds. Based on the combination of these datasets and their comparison with radial seismic models, we propose an average composition model of the Earth's core. We show that the incorporation of small amounts of silicon or oxygen is compatible with geophysical observations and geochemical abundances. The effect of nickel on the calculated light element contents is shown to be negligible. The preferred core model derived from our measurements is an inner core which contains 2.3 wt.% silicon and traces of oxygen, and an outer core containing 2.8 wt.% silicon and around 5.3 wt.% oxygen. (c) 2006 Elsevier B.V. All rights reserved.

    Research areas

  • Earth's core, light elements, high-pressure, seismic wave velocities, solubility, experimental putrology, AB-INITIO CALCULATIONS, HIGH-PRESSURE, INNER-CORE, OUTER CORE, TEMPERATURE, CONSTRAINTS, SULFUR, DENSITY, STATE, MARS

ID: 11477106