Geosc 520 P-T-X PHASE EQUILIBRIA

Instructor:  D.H. Eggler

Text:

Credits: 2- 3

Short Description

This course teaches students the thermodynamic and geometric analysis of phase equilibria in oxide and mineral systems at atmospheric and elevated pressures with and without volatiles components.  Instruction is primarily in one-component and two-component systems, with an introduction to ternaries.  Examples are primarily from systems with applications to geochemical, ore deposit, and igneous or metamorphic petrologic problems, but principles are equally applicable to ceramic and metallic systems.

CONDENSED (CONSTANT PRESSURE OR T-X) PHASE EQUILIBRIA

            BINARY SYSTEMS

               A. Complete miscibility in all phases

                        1. Ab-An: xtalization, melting, assimilation                                

                        2. Ab-An: TSC, ISC, TLC, ILC                                                          

               B. Limited miscibility in one or more phases

                        3. The binary (supposedly) system diopside-anorthite:

                                    the eutectic, experiments, phase rule,

                                    crystallization & melting                                    

                        4. The system forsterite-silica: incongruent melting(peritectic)

                        5. G-X diagrams and thermodynamics  

            TERNARY SYSTEMS

               A. Miscibility gaps (3-phase equilibria)

                        6. Diopside-anorthite-albite                                                      

                        7. odd and even stuff                                                               

                        8. example in forsterite-diopside-silica                          

               B. 4-phase equilibria (eutectics etc.)

                        9. 4-phase equilibria                                                                

                        10. examples in forsterite-diopside-anorthite                             

                        11. Examples in forsterite-diopside-silica                                  

                        12. Fractional fusion and crystallization

            SYSTEMS WITH PRESSURE AS A VARIABLE (P-T-X)

               UNARY (ONE-COMPONENT) SYSTEMS

                        13. Al2SiO5: P-T curves, labeling, & Schreinemakers' rules

                        14. Other unary systems                                                          

               BINARY SYSTEMS

                        15. The P-T-X space model with complete crystalline miscibility

                        16. The P-T-X space model with limited miscibility                   

                        17. Forsterite-silica revisited                                                    

                        18. Nepheline-silica                                         

                        19. critical phenomena: continuous critical curve                       

                        20. example: system H2O-NaCl

            Systems with iron, open binary systems, and chemical potential diagrams

                        21. The system Fe-O

                        22. The system Fe-O in fO2 projection

                        23. Treating Fe-O-S as a unary and Fe-Si-O-S as a binary system

            TERNARY SYSTEMS IN P-T-X

                        24. Examples in KAlSiO4-SiO2-MgO                                    

                        25. Other examples

26. The system Mg-Fe-Si-O: ternary in fO2 projection, with chemical potential diagrams