Unusually Y-rich monazite-(Ce) with 6–14 wt.% Y2O3 in a granulite from the Bohemian Massif: implications for high-temperature monazite growth from the monazite-xenotime miscibility gap thermometry

Abstract

AbstractAccessory monazite-(Ce) with an extraordinarily high proportion of the xenotime component in solid solution of 21–42 mol.% (6.5–14 wt.% Y2O3, 6–11 wt.% HREE2O3) was discovered in a retrogressed Variscan high-pressure, high-temperature granulite from the southern Bohemian Massif, Austria. The grains with the highest proportion of xenotime (XXno ~0.4) should have had a minimum formation temperature of ~1050°C, according to published monazite-xenotime miscibility gap thermometers. This high temperature is consistent with previous petrological studies on the south Bohemian granulites indicating ~1000°C/16 kbar for the peak metamorphic stage.