Electrical Conductivities of Rock-Forming Minerals at High Temperatures

Electrical conductivities of olivine, quartz, garnet, corundum, jadeite and alkali feldspar are measured over the temperature range 500 to 1200°K. Electrical conductivities σ of these rock-forming minerals can be expressed by an equation similar to that for semi-conductors;σ=σ01exp(-ε1/kT)+σ02exp(-ε2/kT)+…where εi's are the activation energies, k, Boltzmann constant and σ0i's, constants. Although the type of conduction mechanism cannot be determined definitely, the activation energies of various rock-forming minerals fall between 0.7 and 1.7eV over the temperature range studied. The pre-exponential term σ0i, however, varies several orders of magnitude for different minerals.