Experimental investigation of electrical conductivity of silicate melts: Implications for melting in Earth’s interior

As silicate melts are electrically more conductive than solid minerals, molten zones in Earth’s interior, such as magma chambers, show anomalies in electrical structure inversed from magnetotelluric survey. To constrain the physicochemical conditions, such as melt fraction and H2O concentration in the melt, of the molten zones, experimental data are urgently needed as to the electrical conductivity of the various silicate melts at different temperatures, pressures and H2O concentrations. This paper reviews the progress in experimental studies of electrical conductivity of silicate melts. The concentration of Na+ and that of H2O are the key factors in controlling electrical conductivity. Two applications include the oceanic asthenospheric low-velocity zone and the magma chamber beneath the Tianchi Volcano, Changbai Mountain. Potential future research directions include electrical investigation of supercritical fluids, which could be deemed as a special type of H2O-rich silicate melt, and determination of melting temperature by using jump in electrical conductivity as an index.