Recalibration of the GASP geobarometer in light of recent garnet and plagioclase activity models and versions of the garnet-biotite geothermometer

Abstract

The garnet-Al silicate-plagioclase (GASP) geobarometer has been recalibrated using four recent garnet activity models, four analogous garnet-biotite temperature models, and two recent plagioclase activity models. A typical sillimanite-bearing sample that formed at about 5.25 kbar, 575 °C shows a possible P range of ~0.7 kbar due to T error, ~1 kbar due to range of garnet activity model, ~0.9 kbar due to range of plagioclase activity model, and ~5.4 kbar due to range of experimental end-member reversals extended by one sigma.