Figure 5.24. Isobaric AFM reaction detail with temperature slider.
Mouseover the diagram to see the bulk composition of the mouse arrow position. Notice the red dot, a pre-selected bulk composition. Then move the slider to examine the mineral assemblage for the red dot bulk composition change due to a continuous chemical reaction as temperature changes. The mode at each temperature is shown numerically and graphically by the colored rectangles for each mineral present, including the projection minerals muscovite (Ms) and quartz (Qz). The Mg/Fe compositions of garnet (Grt), biotite (Bt), and chlorite (Chl) are shown, if the mineral is present, as the molar ratio Mg/(Mg+Fe) -- the Mg#.
Below 559°C and above 602°C, the mineral assemblage for the red dot composition consists of two mineral (plus the projection minerals). Notice that the compositions of the two minerals both change continuously as the temperature is changed, although their proportions are nearly constant. For temperatures between 559°C and 602°C, three minerals (Grt, Bt, and Chl) are present (in addition to Ms and Qz). Notice that the compositions and the proportions of the three minerals both change continuously as the temperature is changed.
AFM reaction details based on the thermodynamic model dataset SPaC (version 4/2000) developed originally by Spear and Cheney (1989). AFM topologies were calculated at temperatures every 0.5°C at and 1.3 Gpa following the procedures of Spear (1999) and converted to SVG files by Frank Spear.
