Thermal conductivity of a volcanic rock material (olivine-melilitite) in the temperature range between 288 and 1470 K

Experimental studies have been performed on the thermal properties of an olivine-melilitite in solid and partly molten states in a temperature range between 288 and 1470 K. Densities (ρ), heat capacities (Cp), and thermal diffusivities (α) were measured by dilatometry, heat flux differential scanning calorimetry, and laser flash analysis and used to calculate the thermal conductivities (λ). In the solid state (288 to 1220 K) ρ decreased from 3091 to 2993 kg/m3, Cp increased from 0.76 to 1.41 J g−1 K−1, α varied between 5.1 and 8.7 10−3 cm2/s, and λ varied between 1.75 and 2.54 W m−1 K−1. In the partly molten state (1300 to 1470 K) Cp increased from 1.56 to 1.70 J g−1 K−1, α decreased from 2.5 to 2.2 10−3 cm2/s, and λ decreased from 1.16 to 1.09 W m−1 K−1. The importance of these data for the physical description of processes acting during explosive volcanic eruptions is discussed.