Metamorphism of High/ultrahigh-pressure Pelitic^Felsic Schist in the SouthTianshan Orogen, NWChina: Phase Equilibria and P^T Path

morphic belt, NW China is characterized by extensive pelitic^felsic schists with numerous blocks of eclogite, ultramafic rock and marble.The pelitic^felsic schists preserve two generations of garnet-bearing mineral assemblages: (1) an early generation that involves garnet, phengite, glaucophane, and quartz/coesite with or without paragonite; (2) a late generation that involves albite, hornblendic amphibole, quartz and grossular-rich, pyrope-poor garnet. Early gen-eration garnet has growth zoning involving core to rim increases in pyrope content, coupled with increased or constant grossular content. Pseudosection modeling of these growth zoning textures in three sam-ples (T311,T314, andT316) reflects prograde paths and peak con-ditions of c. 32 kbar at 550^5708C, c. 22.5 kbar at 5508C, and c. 22^23 kbar at 540^5508C, respectively.These P^T estimates are consistent with those recovered from eclogite blocks hosted by the schists. Phase equilibrium modeling predicts that the early garne