Measurement of thermal properties of select intact and weathered granulites and their relationship to rock properties

Abstract

Understanding the thermal properties of granulites, a group of high-grade metamorphic rocks representing composition of lower crust of the Earth, is necessary to arrive at effective crustal heat flow modeling. However, the thermal conductivity and diffusivity of intact and weathered granulites and parameters that influence them are poorly known. The above properties for a few felsic, mafic, and intermediate granulites and associated soils from the Southern Granulite Terrain, India were investigated using a cost-effective, self-fabricated setup. The results generated by this technique were precise, reproducible, and comparable with other published procedures and values. Because the samples analyzed were of intact in situ specimens, the thermal conductivity and diffusivity could be directly used in practical applications. Among several parameters, it was observed that [Formula: see text] ratio, grain size, and bulk density were the principal factors to influence the conductivity and diffusivity of fresh felsic- and mafic-granulites. For weathered rocks/soils, moisture content, coefficient of uniformity, and fine fractions controlled the thermal properties.