Sound velocity measurement in liquid water up to 25 GPa and 900 K: Implications for densities of water at lower mantle conditions

Yuki Asahara, Motohiko Murakami, Yasuo Ohishi, Naohisa Hirao, Kei Hirose

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

We extended the pressure range of sound velocity measurements for liquid water to 25 GPa and 900 K along the melting curve using a laser heated diamond anvil cell with a combined system of Brillouin scattering and synchrotron X-ray diffraction. Experimental pressure and temperature were obtained by solving simultaneous equations: the melting curve of ice and the equation of state for gold. The sound velocities obtained in liquid water at high pressures and melting temperatures were converted to density using Murnaghan's equation of state by fitting a parameter of the pressure derivative of bulk modulus at 1 GPa. The results are in good agreement with the values predicted by a previously reported equation of state for water based on sound velocity measurements. The equation of state for water obtained in this study could be applicable to water released by dehydration reactions of dense hydrous magnesium silicate phases in cold subducting slabs at lower mantle conditions, although the validity of Murnaghan's equation of state for water should be evaluated in a wider pressure and temperature ranges. The present velocity data provides the basis for future improvement of the accurate thermodynamic model for water at high pressures.

Original languageEnglish
Pages (from-to)479-485
Number of pages7
JournalEarth and Planetary Science Letters
Volume289
Issue number3-4
DOIs
Publication statusPublished - 2010 Jan 31

Keywords

  • Brillouin scattering
  • diamond anvil cell
  • lower mantle
  • sound velocity
  • synchrotron X-ray diffraction
  • water

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

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