Figure 6.11. Thermobarometry Example. Temperatures of metamorphosed shales using the compositions of garnet and biotite based on the experiments of Ferry and Spear (1978) and using equation 15-44 of Spear (1993) are shown with a red line. Pressures of metamorphosed shales using the compositons of coexisting garnet and plagioclase based on the GASP barometer data of Koziol and Newton (1988) using equation 15-48 of Spear (1993) are shown with a green line. Move the sliders to change the KD or Keq values or the mineral compositions, or enter values into the boxes. Click on the "Coordinate" buttons and mouseover the intersection of the two colored lines to see the T and P calculated with this thermobarometry model. Other reference reactions can be shown by clicking on the appropriate check boxes. Reactions for metamorphosed shale subsystems from the thermodynamic model dataset SPaC (version 4/2000) developed originally by Spear and Cheney (1989) may be shown by checking the boxes KASH, KFASH, KMASH, and KFMASH.