P-T path determination using phase equilibria modelling with multiple fractionation of garnet in a metapelite

CARLOS IVÁN LEMBO WUEST; SAMANTA SERRA VARELA; SEBASTIAN VERDECCHIA; JUAN MURRA; MANUELA BENITEZ; GLADIS PALACIO BALDERRAMO

Taller; Metamorphic Studies Group Research in Progress Meeting; 2020

Zoned garnets are considered useful to determine prograde metamorphic evolution, in which a fractionation of chemical components from whole-rock composition occurs. Thus, effective bulk composition (EBC) should change while garnet is growing to remove the essential components used for its nucleation. Therefore, a step-by-step estimate of the equilibrium volume is necessary to reconstruct the P-T path toward the metamorphic peak. In this work, we analyze a metamorphic P-Tpath for a garnet mica-schist from Sierra El Gigante (Argentina) using multiple fractionations of garnet in conjunction with P-T pseudosections and compositional isopleths based on chemical mineral analysis.