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 K_D or K_eq 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.

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