GrtBt&Facies4 0.3 0.0 1.2 1.5 0 400 200 600 800 1000 T emperature (°C) Pressure (GPa) eclogite granulite blueschist zeolite Prh- Pmp greenschist amphibolite Ep-Amp Sil And Ky wet granite melting Jd + QzAb ArgCc KASH PrlKy+Qz PrlAnd+Qz KyAnd KyAnd KySil Ms+QzSil+Kfs+L KFASH Hc+VFeCrd Alm+SilHc Alm+AlsFeCrd Ann+AlsFeCrd FeCrd+AnnAlm AlmAnn+Als StAlm+Als Cld+AlsSt CldAlm+Als AlmChl AlmAnn+Cld CldAlm+St AlmAnn+St StAnn+Als An+CldAlm FeChlAnn+Cld Ms+QzAls+Kfs+Bt KMASH Chl+AlsMgCrd PhlEn+MgCrd+Kfs+L Als+EnMgCrd Als+BtMgCrd Als+PhlMgCrd+Kfs+L LPhl+Kfs+V ChlAls+Bt ChlCrd+Bt KFMASH Als+BtGrt+Crd Grt+SilSpl+Crd ChlCrd+Bt+Sil CldSt+Grt+Bt Cld+ChlSt+Bt St+ChlCrd+Bt+Sil Cld+AlsSt+Chl Grt+Chl Cld+Bt Grt+ChlSt+Bt CldGrt+St+Chl Grt+ChlAls+Bt CldGrt+Als+Chl Grt+Cld+AlsSt Grt+Chl+Als St Grt+Bt+AlsSt Ms+QzAls+Kfs+Bt Ms+QzAls+Kfs+L Bt+GrtOpx+Als+L Bt+GrtOpx+Crd+Kfs+V LKfs+Grt+Crd+Bt+V Ms+VAls+L Bt+GrtOpx+Crd+L Opx+Als Grt+Crd Bt+AlsGrt+Crd+L Bt+AlsOpx+Crd+L Bt+GrtOpx+Als+L Bt+AlsGrt+Crd+L Opx+AlsGrt+Crd Bt+GrtOpx+Crd+V Ms+Ab+VAls+L Ms+AbAls+Kfs+L Bt+GrtOpx+Crd+L Bt+AlsOpx+Crd+L Grt+SilSpl+Crd Ms+AbAls+Kfs+V NaKFMASH

Als Granite Facies
CcArg AbJdQz

Garnet-Biotite Mg-Fe
Exchange Coefficient (KD)

Garnet XMg (Mg/Fe)Grt

Biotite XMg (Mg/Fe)Bt

Grt-Als-Qt-Pl (GASP)
Equilibrium Constant (Keq)

Garnet XCa

Plag XCa

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.