An anisotropic equation of state for solid solutions, with application to plagioclase

This paper presents a framework for building anisotropic equations of state for solid solutions. The framework satisfies the connections between elastic and thermodynamic properties required by Maxwell’s reciprocal relations. It builds on a recent anisotropic equation of state for pure phases under small deviatoric stresses, adding a dependence on a vector n, whose components ni contain the molar amounts of independent endmembers in a solid solution. These endmembers may have distinct chemical compositions, site species occupancies or electronic spin states. The high albite-anorthite (Cbar1) plagioclase solid solution is used to illustrate the formulation.