|
School of Earth Sciences, The University of Melbourne, Parkville, Victoria 3052, Australia
Department of Geology and Geophysics, University of Adelaide, S.A. 5005, Australia
Quantitative phase diagrams, and in particular phase diagram movies, offer a powerful and versatile forward approach to modelling the P-T-x-t relationships of natural mineral assemblages. Phase diagram movies are ideal for illustrating the continuous way in which mineral compositions and assemblages evolve with changing P-T-x conditions. A feature of the animation process, is that it also enables an extra variable to be represented by the running time of the movie. A methodology for producing quantitative phase diagram movies is illustrated using the example of the AFM compatibility diagram. This approach involves the calculation of phase equilibria at critical values of the animating variable (in this case temperature), with interpolation of the data between these values. Phase equilibria calculations were performed using Thermocalc v2.5, and data interpolation and construction of the individual phase diagrams (or movie frames) was achieved in Mathematica® v2.2.2 using purpose-written code. Although the details of the technique, and the code, have been designed for use with this particular application, the approach is quite general.
