Thermal and transport properties of mafic and ultramafic rocks of Oman ophiolite

Abstract EN

Thermal and other physical properties of rocks and minerals are of considerable significance for deriving mineralogical and compositional models of the Earth's mantle.

We have determined these properties for the mafic rock such as gabbro and ultramafic rock like harzburgite of the Oman ophiolite suite by utilizing the Debye characteristic property .

forms the basis of our present investigation and allows us to evaluate their melting temperature Tm, thermal conductivity KL and diffusivity D.

Their seismic velocities and the density data are used, a priori, to determine the Debye temperature of these rocks.

Different thermoelastic and thermodynamic relations are further used to investigate the above properties as a function of temperature, T.

Our analysis shows that is temperature dependent, indicating the presence of vibrational modes other than the Debye distribution in the gabbro and harzburgite of the Oman ophiolite.

Results suggest that the thermal properties such as , Tm and specific heat capacity and transport properties such as KL, D and viscosity, of ultramafic rock (harzburgite) are higher than those of mafic rock, indicating the influence of an olivine content in the former.

decreases with increasing temperature but increases with increasing pressure, P.

Similarly, compressibilities increase for both rocks with increasing T but decrease with increasing P.

The trends of variation of thermal conductivity and diffusivity with temperature and pressure are opposite.

KL and D decrease with increasing T but are found to increase with increasing P.