Effect of hydrostatic pressure on the lattice parameters of Fe2SiO4 olivine up to 70 kbar

摘要: The pressure dependence of the three lattice parameters and unit cell volume fayalite (Fe2SiO4 olivine) was determined by X-ray diffraction under hydrostatic pressures up to 70 kbar. In order eliminate stress inhomogeneity within a composite material consisting specimen mixed with an internal-pressure standard, liquid (1 : 1 mixture ethanol methanol) used as pressure-transmitting medium. isothermal bulk modulus calculated on basis second-order Birch-Murnaghan equation state gives values K0 = 1.19 ± 0.10 Mbar K0′ 7 4, if we assume 5: 1.24 0.02 Mbar. Three axes were found be compressible in following order, b >c >a. Comparisons results obtained non-hydrostatic compression are made.