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Physics and Chemistry of Minerals

, Volume 29, Issue 1, pp 1–9 | Cite as

Equation of state, elasticity, and shear strength of pyrite under high pressure

  • S. Merkel
  • A. P. Jephcoat
  • J. Shu
  • H.-K. Mao
  • P. Gillet
  • R. J. Hemley
ORIGINAL PAPER

Abstract

 Physical properties including the equation of state, elasticity, and shear strength of pyrite have been measured by a series of X-ray diffraction in diamond-anvil cells at pressures up to 50 GPa. A Birch–Murnaghan equation of state fit to the quasihydrostatic pressure–volume data obtained from laboratory X-ray source/film techniques yields a quasihydrostatic bulk modulus K 0T =133.5 (±5.2) GPa and bulk modulus first pressure derivative K 0T =5.73 (±0.58). The apparent equation of state is found to be strongly dependent on the stress conditions in the sample. The stress dependency of the high-pressure properties is examined with anisotropic elasticity theory from subsequent measurements of energy-dispersive radial diffraction experiments in the diamond-anvil cell. The calculated values of K 0T depend largely upon the angle ψ between the diffracting plane normal and the maximum stress axis. The uniaxial stress component in the sample, t3−σ1, varies with pressure as t=−3.11+0.43P between 10 and 30 GPa. The pressure derivatives of the elastic moduli dC11/dP=5.76 (±0.15), dC12/dP=1.41 (±0.11) and dC44/dP=1.92 (±0.06) are obtained from the diffraction data assuming previously reported zero-pressure ultrasonic data (C11=382 GPa, C12=31 GPa, and C44=109 GPa).

Keywords High pressure Elasticity Pyrite Shear strength Radial diffraction 

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Copyright information

© Springer-Verlag Berlin Heidelberg 2002

Authors and Affiliations

  • S. Merkel
    • 1
  • A. P. Jephcoat
    • 2
  • J. Shu
    • 1
  • H.-K. Mao
    • 1
  • P. Gillet
    • 1
  • R. J. Hemley
    • 1
  1. 1.Geophysical Laboratory and Center for High-Pressure Research, Carnegie Institution of Washington, 5251 Broad Branch Rd., NW, Washington DC 20015-1305, USA, e-mail: merkel@gl.ciw.eduUS
  2. 2.Department of Earth Sciences, University of Oxford, Parks Road, Oxford OX1 3PR, UKGB

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