How water could affect thermal transport properties is a key question that needs to be quantified experimentally when it is incorporated as structurally bound hydroxyl groups in the lattice of mantle minerals. In this study, thermal diffusivity (D) and thermal conductivity (κ) of San Carlos olivine aggregates with various water contents (up to 0.2 wt.% H2O) were measured simultaneously using transient plane‐source method up to 873 K and 3 GPa. Experimental results demonstrate that water content can significantly reduce the thermal diffusivity (D) and thermal conductivity (κ) of olivine aggregate. With the increase of H2O content from 0.08 to 0.2 wt.%, the absolute values of D and κ for olivine samples decrease by 5–13% and 17–33% and by 3–8% and 14–21%, respectively. D and κ of olivine aggregate decrease with temperature but increase with pressure. Heat capacity is influenced by pressure negatively. Combining the present data with surface heat flow of the Moon as well as heat production, the calculated temperature profiles provide new constraints on the lunar geotherm and possible H2O content in the lunar interior.

The thermal diffusivity and thermal conductivity of four natural granitoid samples were simultaneously measured at high pressures (up to 1.5 GPa) and temperatures (up to 988 K) in a multi-anvil apparatus using the transient plane–source method. Experimental results show that thermal diffusivity and thermal conductivity decreased with increasing temperature (<600 K) and remain constant or slightly increase at a temperature range from 700 to 988 K. Thermal conductivity decreases 23–46% between room temperature and 988 K, suggesting typical manifestations of phonon conductivity. At higher temperatures, an additional radiative contribution is observed in four natural granitoids. Pressure exerts a weak but clear and positive influence on thermal transport properties. The thermal diffusivity and thermal conductivity of all granitoid samples exhibit a positive linear dependence on quartz content, whereas a negative linear dependence on plagioclase content appears. Combining these results with the measured densities, thermal diffusivity, and thermal conductivity, and specific heat capacities of end-member minerals, the thermal diffusivity and thermal conductivity and bulk heat capacities for granitoids predicted from several mixing models are found to be consistent with the present experimental data. Furthermore, by combining the measured thermal properties and surface heat flows, calculated geotherms suggest that the presence of partial melting induced by muscovite or biotite dehydration likely occurs in the upper-middle crust of southern Tibet. This finding provides new insights into the origin of low-velocity and high-conductivity anomaly zones revealed by geophysical observations in this region.