geothermobarometry

Geothermobarometry is the methodology for estimating the pressure and temperature history of rocks (metamorphic, igneous, or sedimentary). Geothermobarometry is a combination of geobarometry, where the pressure attained (and retained) by a mineral assemblage is estimated, and geothermometry where the temperature attained (and retained) by a mineral assemblage is estimated. thumb|upright=1.35|An illustration of geothermobarometry. A line of temperature equilibrium (orange) and a line of pressure equilibrium (blue) of selected mineral assemblages found in the specimen are plotted on the P-T diagram. The intersection represents the likely P-T condition experienced by rock in its metamorphic history.

==Methodology== Geothermobarometry relies upon understanding the temperature and pressure of the formation of minerals within rocks. There are several methods of measuring the temperature or pressure of mineral formation or re-equilibration relying for example on chemical equilibrium between minerals, or by measuring the chemical composition and/or the crystal-chemical state of order of individual minerals, or by measuring the residual stresses on solid inclusions or densities in fluid inclusions.