Physical properties of Earth materials

Abstract

Knowledge of the physical properties of minerals and silicate melts is important because the Earth is dynamic, not static, and most of the geologic processes that occur in it are the results of motion. The movement causes disruption of equilibrium. For instance, density differences cause magma to rise so that both the magma and its country rock encounter new P—T regimes. The rate and mechanism of rise depends on many physical properties, including the density and viscosity of the magma and of the country rock. The rates at which the magma crystallizes and the country rocks react control how closely equilibrium is approached, and determine the rate at which heat is consumed or released by the process. Thus in order to develop large scale models for Earth processes, we must know the densities, viscosities, diffusion coefficients, crystal growth rates, and elastic properties of crystals and melts.