Recalibration of the 5-parameter MRK equation of state for C-O-H fluids under upper mantle conditions and some experimental tests

Abstract

An extensive series of experiments in the system C-O-H fluid + graphite at 2.4 GPa and 1000°C was undertaken by Matveev et. al. (1997). The fluids were either unbuffered or were buffered by various metal-oxide oxygen buffers and fluid analyses were undertaken by a capsule piercing-gas chromatography technique. Numerous experimental tests showed that the fluid analyses reflected those of high-P,T equilibrium, i.e. quench modification processes were generally not significant provided maximum quench rates were employed. One goal of these experiments was to develop an equation of state (EOS), or modify an existing EOS, for supercritical C-O-H fluids in order to better estimate species activities and distributions under upper mantle P, T, f02 conditions.