Abstract:This paper reports a felsic vein in host mafic granulite from the Bashiwake area, South Altyn Tagh. Zircon grains yield a weighted mean 206Pb/238U age 491±2 Ma (MSWD=0.91). The characteristics of zircon morphology, mineral inclusions, low Th/U values, HREE enrichment, and obviously negative Eu anomalies indicate these zircons from felsic veins was formed from the metamorphic melts. The U-Pb age of 491±2 Ma is consistent with the zircon U-Pb age of host mafic granulite, which was interpreted the peak metamorphic age. Thus, the felsic veins from the host mafic granulite may be formed at the peak metamorphic event. The similarity of Hf isotope features between the felsic vein and host mafic granulite indicate the melt may be an internal source, and on the basis of whole-rock geochemistry, it is generated by the partial melting of the host mafic granulite.