Physics and Chemistry of Minerals

, Volume 38, Issue 10, pp 767–776

Melting of Fe–Ni–Si and Fe–Ni–S alloys at megabar pressures: implications for the core–mantle boundary temperature

  • Guillaume Morard
  • Denis Andrault
  • Nicolas Guignot
  • Julien Siebert
  • Gaston Garbarino
  • Daniele Antonangeli
Original Paper

DOI: 10.1007/s00269-011-0449-9

Cite this article as:
Morard, G., Andrault, D., Guignot, N. et al. Phys Chem Minerals (2011) 38: 767. doi:10.1007/s00269-011-0449-9

Abstract

High pressure melting behavior of three Fe-alloys containing 5 wt% Ni and (1) 10 wt% Si, (2) 15 wt% Si or (3) 12 wt% S was investigated up to megabar pressures by in situ X-ray diffraction and laser-heated diamond anvil cell techniques. We observe a decrease in melting temperature with increasing Si content over the entire investigated pressure range. This trend is used to discuss the melting curve of pure Fe. Moreover, our measurements of eutectic melting in the Fe–Fe3S system show a change in slope around 50 GPa concomitant with the fcc–hcp phase transition in pure solid iron. Extrapolations of our melting curve up to the core–mantle boundary pressure yield values of 3,600–3,750 K for the freezing temperature of plausible outer core compositions.

Keywords

Iron alloys melting temperatureHigh pressureCore–mantle boundary

Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Guillaume Morard
    • 1
  • Denis Andrault
    • 2
  • Nicolas Guignot
    • 3
  • Julien Siebert
    • 1
  • Gaston Garbarino
    • 4
  • Daniele Antonangeli
    • 1
  1. 1.Institut de Minéralogie et de Physique des Milieux Condensés, UMR CNRS 7590, Institut de Physique du Globe de ParisUniversité Pierre et Marie CurieParisFrance
  2. 2.Laboratoire Magmas et VolcansUniversité Blaise PascalClermont-FerrandFrance
  3. 3.Synchrotron SOLEILGif-sur-YvetteFrance
  4. 4.European Synchrotron Radiation FacilityGrenobleFrance