SHRIMP U-Pb dating of zircons from blueschist in the central part of the Qiangtang block, northern Tibet, China, and its implications.

SHRIMP U-Pb dating of zircons from two blueschist samples in central Qiangtang, northern Tibet, suggests that the zircons in blueschist are relict ones rather than neogenic ones formed by blueschist facies metamorphism. These ages stand for those of protoliths in source regions or those of zircons captured by protoliths and are responses to different tectonothermal events. The SHRIMP U-Pb zircon age of 2533 Ma obtained for the first time in the central Qiangtang area, northern Tibet, indicates that the zircon originated from the Late Archean rocks, and although the zircon may not necessarily have originated in the study area, its age at least implies that a tectonothermal event may have occurred in the Qiangtang area in the late Archean.