LA-ICP-MS zircon U-Pb ages and Hf isotopic characteristics of Wuxukelaoge pluton in East Junggar Basin of Xinjiang and their geological significance

Thanks to prospecting breakthrough in recent years, a series of important mineral resources have been found in Qionghebagion and it has a complex composition, mainly comprising granodiorite and monzonitic granite. In this paper, U-Pb dating of LAICP-MS zircon was used to investigate the age of the pluton. It is shown that granodiorite is 428.9±1.9Ma and monzonitic granite is 427.2±1.7Ma in age, suggesting that the two ages represent the ages of rocks that contain the zircon. Both the granodiorite and mon-zonitic granite are of peraluminous and calc-alkaline series with high Al₂O₃ (15.87%~18.77%), CaO (2.92%~6.82%) and low K₂O/Na₂O ratios (0.15~0.40); The pluton has low total REE content (57.33×10^-6~72.13×10^-6) with relative enrichment of LREE and ob-scure Eu negative anomaly (δEu=0.79~1.06). The primitive mantle normalized trace element patterns are characterized by the deple-tion of the HFSE (Th, Nb, Ta, P, Ti) and enrichment of the LILE (Rb, Ba, U, K, Sr). High Ba (230×10^-6~682×10^-6), Sr(851.8×10^-6~1020.1×10^-6), high (La/Yb)N(6.0~10.1), Sr/Y(70.0~106.4) ratios, and distinct Nb all suggest features of high Ba-Sr granitoids. The test results of Hf isotope show that Wuxukelaoge pluton has high and positive εHf(t) values(14.28~17.54) and younger model age. These geochemical and Hf isotope characteristics indicate that the pluton was formed in a continental margin arc setting and related to partial melting of subducted oceanic crust. area, East Junggar Basin, Xinjiang, which are essentially distributed around Wuxukelaoge pluton. The pluton is the largest in the re-