## Abstract

Hydrostatic compression data for a number of high-pressure phases of oxides and silicates, which have been studied independently by acoustic techniques, have been analyzed by least-squares fitting of the Birch-Murnaghan equation of state to determine the zero-pressure bulk modulus K_{0} and its pressure derivative K′_{0} for each material. The standard deviations of K_{0} and K′_{0} so determined are generally underestimated unless the experimental errors in the measurements of volume and pressure are explicitly included. When the values of K_{0} determined from the acoustic and compression techniques are consistent, test results for quartz and rutile demonstrate that constraining K_{0} to be equal to the acoustic value significantly improves both the accuracy and the precision of K′_{0} obtained from the compression data. Similar analyses for high-pressure phases (e.g., pyrope garnet and silicate spinels) indicate that by combining the acoustic and P-V data, the standard deviation of K′_{0} is typically reduced by a factor of three. Thus, we conclude that this approach does allow precise determinations of K′_{0} even when neither technique alone is able to resolve this parameter. For some materials, however, the P-V and acoustic experiments do not define mutually consistent values of K_{0}, invalidating any combination of these data. The compression data for stishovite clearly exhibit run to run effects, and we infer that systematic errors are present in some of the P-V data which are responsible for many of the interlaboratory inconsistencies. Such systematic biases in the P-V data can at least be partially compensated for by performing several duplicate experimental runs.

Original language | English (US) |
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Pages (from-to) | 140-158 |

Number of pages | 19 |

Journal | Physics of the Earth and Planetary Interiors |

Volume | 25 |

Issue number | 2 |

DOIs | |

State | Published - Apr 24 1981 |

Externally published | Yes |

## ASJC Scopus subject areas

- Astronomy and Astrophysics
- Geophysics
- Physics and Astronomy (miscellaneous)
- Space and Planetary Science