Precalculated phase equilibrium models for geophysical properties of the crust and mantle as a function of composition

The use of phase equilibrium calculations to compute physical properties of rocks has become commonplace in geophysical modeling. Typically, the phase equilibrium calculations are used to construct two-dimensional tables of rock properties as a function of pressure and temperature. We document a computer program that can be used to assemble a three-dimensional table that accounts for compositional variations from such two-dimensional tables. A user-selected interpolation scheme is used to recover data from the tables as continuous function of its independent variables. We illustrate the utility of the program using two examples. The first explores the effect of water content of an average continental crust composition. As water content is the primary parameter controlling the amount of melt and/or low-density fluid present in the crust, this model provides a basis for assessing the impact of fluids on the geophysical properties of the crust. In the second example, we model the mantle composition as a mixture between harzburgitic and basaltic end-members. We show that for purposes of seismic velocity calculations, the continuum model is well approximated by interpolation from a table in which the compositional variable is sampled at 10% intervals. The tables for both examples are provided electronically as ready-to-use geophysical tools.