Geothermobarometry. How do we know P and T?. Need min. at equilibrium. Good barometer rxn vs. good thermometer rxn Which has large D V and which has large D S?. D. dP. S. =. D. dT. V. Geothermobarometry.
Need min. at equilibrium
Good barometer rxn vs. good thermometer rxn
Which has large DV and which has large DS?
Measure distribution of elements in coexisting phases from experiments at known P and T
Estimate P and T of equilibrium in natural samples
Garnet-biotite exchange reaction
Bigger K: Mg-rich garnet or Fe rich biotite
Smaller K: Mg-rich biotite or Fe-rich garnet