Prediction of silicate melt viscosity from electrical conductivity: A model and its geophysical implications

Abstract

Abstract Our knowledge of magma dynamics would be improved if geophysical data could be used to infer rheological constraints in melt‐bearing zones. Geophysical images of the Earth's interior provide frozen snapshots of a dynamical system. However, knowledge of a rheological parameter such as viscosity would constrain the time‐dependent dynamics of melt bearing zones. We propose a model that relates melt viscosity to electrical conductivity for naturally occurring melt compositions (including H 2 O) and temperature. Based on laboratory measurements of melt conductivity and viscosity, our model provides a rheological dimension to the interpretation of electromagnetic anomalies caused by melt and partially molten rocks (melt fraction ~ >0.7).