This is a continuation of research previously supported by NSF grant EAR83-19084, involving the direct determination of thermodynamic properties of important minerals by solution calorimetry. The research will yyield excess enthalpies and volumes associated with chemical substitution in muscovite- paragonite micas, nepheline- analcite-leucite. Enthalpies of formation will be determined for paragonite and sodalite. Enthalpy changes associated with strain will be measured in crypto-perthites. Excess entropies will be formulated in alkali feldspars by combining calorimetric results with data from phase equilibrium studies. The proposed projects have not been attempted previously and thus will lead to new data on these minerals.
