Tracking the thermal properties of the lower continental crust: Measured versus calculated thermal conductivity of high-grade metamorphic rocks (Southern Granulite Province, India)

•Bulk thermal conductivity (TC) of granulites is measured by optical-scanning method.•Mineralogical composition of these rocks is determined by XRD and EPMA.•Bulk TC is calculated from modal mineralogy using various mixing models.•TC of minerals play a vital role in the calculation of bulk TC.•TC at ambient condition for lower crustal rocks ranges between 2 and 3Wm−1K−1. In this study, the bulk thermal conductivity (TC) of 26 rock samples representing different types of granulite-facies rocks, i.e., felsic, intermediate and mafic granulites, from the Southern Granulite Province, India, is measured at dry and saturated conditions with the optical-scanning method. Thermal conductivity is also calculated from modal mineralogy (determined by XRD and EPMA), applying several mixing models commonly used in thermal studies. Most rocks are fine- to medium-grained equigranular in texture. All samples are isotropic to weakly anisotropic and possess low porosities (