Elastic wave velocities and Raman shift of MORB glass at high pressures

Yoshio Kono, Hiroaki Ohfuji, Yuji Higo, Akihiro Yamada, Toru Inoue, Tetsuo Irifune, Ken Ichi Funakoshi

Research output: Contribution to journalArticlepeer-review

Abstract

The elastic wave velocities of MORB glass were measured up to 18.7 GPa at 27 °C using an ultrasonic technique combined with in situ high-pressure X-ray diffraction and imaging. High-pressure Raman spectroscopy using a diamond anvil cell was also employed to study the local structure of the glass sample up to 20 GPa. Both the elastic wave velocities and Raman frequency at ∼ 1600 cm1 show significant changes in their pressure dependences at ∼ 10 GPa. The pressure derivatives of the P-wave and bu k sound velocities gradually increase with pressure above ∼ 10 GPa, whereas the S-wave velocity is almost constant below 10 GPa, above which it increases significantly. The plot of apparent change in the Raman frequency shift versus pressure suggests that these notable changes in elastic properties may be attributed to the local structural changes in the MORB glass. Our observations demonstrate that both the density and adiabatic bulk modulus of the MORB glass increase continuously at pressures above ∼ 10 GPa. These apparently conflicting tendencies can be reasonably explained if the zero-pressure density is increased continuously above ∼ 10 GPa accompanied by structural modification. Since the fundamental structure of silicate glass is analogous to that of melt, the results are important and aid in understanding the elastic properties of silicate melt at high pressures.

Original languageEnglish
Pages (from-to)126-130
Number of pages5
JournalJournal of Mineralogical and Petrological Sciences
Volume103
Issue number2
DOIs
Publication statusPublished - 2008
Externally publishedYes

Keywords

  • Elastic wave velocity
  • Glass
  • High pressure
  • MORB
  • Raman frequency shift

ASJC Scopus subject areas

  • Geophysics
  • Geology

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