History of zircon growth in a high-pressure granulite within the eastern himalayan syntaxis, and tectonic implications

High-pressure (HP) granulites exposed within the eastern Himalayan syntaxis are dominantly felsic rocks. They were displaced southward over the Pei sequence by the NW-dipping Upper Thrust. Tiventy-three SHRIMP U/Pb analyses of zircons froin one HP sample denionstrate that this rock was derived from Proterozoic sedirnentary rocks that underwent high-teroperature nielaruorphisin of- partial melting to forin granitoids or paragneisses at about 500 Ma. During Oligocene collision between India and Asia, these crystalline rocks were buried beneath soulli Tibet, recrystallizing to forin HP felsic granulites at 30-33 Ma, with a nietarnorphie retrogression at about 23 Ma. E.vidently the South Tibetan crust was thickened, and then uplifted at this finie.