Elasticity of MgO to 11 GPa with an independent absolute pressure scale: Implications for pressure calibration

Baosheng Li, Kelly Woody, Jennifer Kung

Research output: Contribution to journalArticle

51 Citations (Scopus)

Abstract

P and S wave velocities and unit cell parameters (density) of MgO are measured simultaneously up to 11 GPa using combined ultrasonic interferometry and in situ X-ray diffraction techniques. The elastic bulk and shear moduli as well as their pressure derivatives are obtained by fitting the measured velocity and density data to the third-order finite strain equations, yielding Kos = 163.5(11) GPa, K'os = 4.20(10), Go = 129.8(6) GPa, and G'o = 2.42(6), independent of pressure. These properties are subsequently, used in a Birch-Murnaghan equation of state to determine the sample pressures at the observed strains. Comparison of the 300K isothermal compression of MgO indicates that current pressure scales from recent studies are in better than 1.5% agreement. We find that pressures derived from secondary pressure standards (NaCl, ruby fluorescence) at 300K are lower than those from current MgO scales by 5-8% (∼6% on average) in the entire pressure range of the current experiment. If this is taken into account, discrepancy in previous static compression studies on MgO at 300K can be reconciled, and a better agreement with the present study can be achieved.

Original languageEnglish
Article numberB11206
JournalJournal of Geophysical Research: Solid Earth
Volume111
Issue number11
DOIs
Publication statusPublished - 2006 Nov 4

All Science Journal Classification (ASJC) codes

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

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