This activity would be used in an undergraduate (sophomore or junior level) required course in petrology.

Students should have a general understanding of phase equilibria and general physics and mineralogy.

This is a stand-alone exercise.

The main goals are to help students understand how thermodynamics can be useful for solving real geologic problems, to provide some insights into the nature and construction of P-T phase diagrams, and to provide experience in dealing quantitatively with real data.

This activity involves analyzing data.

In this problem set students construct a P-T phase diagram for the aluminosilicate polymorphs based on experimental phase equilibria and application of the Clausius-Clapeyron equation. The problem set uses unit cell volume, molar entropy, and phase equilibrium data culled from the primary literature. It leads students through the exercise in step-by-step fashion starting with a brief explanation of the Clausius-Clapeyron equation. The main goals are to help students understand how thermodynamics can be useful for solving real geologic problems, to provide some insights into the nature and construction of P-T phase diagrams, and to provide experience in dealing quantitatively with real data.

Students have met the goals of this activity if they answer the problem set questions thoroughly and accurately.