This project is a continuation of research previously supported by NSF grant EAR 84-16254, involving experimental studies of the phase equilibria of common rock-forming minerals. Reversed phase equilibrium experiments, coupled with thermodynamic modelling of the experimental results, will provide the basis for determination of the temperature, pressure, and oxidation conditions during the formation of rocks containing these minerals. Specific objectives of the project include (1) continued experiments on ternary feldspars, (2) examination of the effects of barium on two- feldspar equilibria, (3) continued experiments on the effects of minor components on iron-titanium oxide equilibria, and (4) study of the stability of titanium-bearing biotite. The results of these studies will increase our understanding of the behavior of common rock-forming minerals under diverse conditions of pressure and temperature, and will provide improved methods for determining the conditions of formation of geological materials.
