The compressibility of Forsterite up to 300 kbar measured with synchrotron radiation

The effect of pressure on the lattice constants and therefore the volume of synthetic forsterite was determined by energy-dispersive X-ray diffraction from polycrystalline material using synchroton radiation from the storage-ring DORIS at the HASYLAB, DESY (Hamburg). Pressures up to 300 kbar were applied with a diamond-anvil cell. The pressures were calculated from the volume compression by internal standard method using MgO, Fe and NaCl as pressure calibrants. The isothermal bulk modulus K0 and also its first pressure derivative K0′ (at 25°C) of forsterite have both been obtained from the experimental data with the Murnaghan equation of state by a two parameter fit yielding K0 = 1357(10) kbar and K0′=3.98(10) (standard deviations in parentheses). We found no differences with the different marker.