The geochemical analysis of the amphibolite in the east of Qikeshan indicates it belongs to tholeiitic series with high SiO2 and Al2O3 contents of 46.99%~51.01% and 13.85%~15.82%, MgO and FeOT contents of 7.00%~7.71% and 12.4%~13.5%. Diagrams of MgO vs. SiO2, Al2O3, CaO and FeOT, Cr vs. Rb and Rb/Nb vs. Rb/Zr exhibit that partial melting and fractional crystallization has occurred in the magma evolution. And the slightly enrichment of light rare earth element (LREE) implies the magma has experienced a 10% to 20% of partial melting and low fractional crystallization. Zircon Lu Hf isotopic data reveal that the protolith was from the mantle derived magma which was slightly differentiated from the chondrite, and the liquid temperature of the magma was 1175~1251℃. Microanalytical dating shows the protolith has an age of 718±22Ma with a metamorphic age of 502±14Ma. The new data and previous studies indicate that the protolith was not the product of the Neoarchean Era, but formed in the expansion period after the assembly of the Neoproterozoic Rodinia supercontinent, and experienced the peak metamorphism of early Paleozoic South Altyn, revealing that the original ancient Tethys was closed in 502±14 Ma.