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

CARLOS IVAN LEMBO WEST; SAMANTA SERRA VARELA; SEBASTIAN OSVALDO VERDECCHIA; JUAN MURRA; MANUELA BENITEZ; GLADIS PALACIO BALDERRAMO

Londres

Encuentro; Metamorphic Studies Group reserch in progress; 2020

Mineralogical society

Zoned garnets are considered useful to determine prograde metamorphic evolution, in which afractionation of chemical components from whole-rock composition occurs. Thus, effective bulkcomposition (EBC) should change while garnet is growing to remove the essential components usedfor its nucleation. Therefore, a step-by-step estimate of the equilibrium volume is necessary toreconstruct 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 ofgarnet in conjunction with P-T pseudosections and compositional isopleths based on chemicalmineral analysis.