Thermal Diffusivity and Heat of Formation of Harzburgite and Its Major Constituent Minerals

The thermal diffusivity, D, and its temperature dependence of Oman harzburgite rock and its major mineral olivine have been evaluated from the basic properties such as seismic velocities, density, and Debye temperature. The Arrhenius-type temperature dependence of the diffusivity was utilized to evaluate the heat of formation, Delta H (D). The diffusivity values, 1.80mm(2) center dot s(-1) and 2.1mm(2) center dot s(-1) obtained at room temperature for harzburgite and olivine, respectively, are consistent with available data. The diffusivity values for Oman harzburgite are overestimated by an amount of 0.27mm(2) center dot s(-1) relative to those of PNG harzburgite. The Delta H (D) value (-2.40 kJ center dot mol(-1)) for harzburgite rock of the Oman ophiolite suite is comparable with that (-2.90 kJ center dot mol(-1)) of the harzburgite rock of Papua New Guinea. The disagreements in the thermal diffusivity and heat of formation values may be partly due to ignoring the effect of pyroxene in Oman harzburgite.