Petrological and geochronological constraints on the origin of HP and UHP kyanite-quartzites from the Sulu orogen, Eastern China

Kyanite (Ky)-quartzites occur in both the high-pressure (HP) and ultrahigh-pressure (UHP) metamorphic belts in the southern Sulu orogen. The HP Ky-quartzites consist of quartz, kyanite and minor rutile with or without topaz and phengite, whereas those from the UHP unit consist of quartz, kyanite, phengite and rutile. The HP Ky-quartzites are characterized by high Al2O3 (up to 32.9 wt.%) and low SiO2 (down to 60.4 wt.%) with very low other oxides contents (