Rock-forming and ore-forming ages and geochemistry of the Layikeleke porphyry Cu(Mo) deposit in East Junggar of Xinjiang and their geological significance

The Layikeleke deposit is a concealed porphyry deposit newly discovered by comprehensive geoprehensive exploration in Quaternary coverage area. In this paper, U-Pb dating of LA-ICP-MS zircon and dating of Re-Os isotope and Hf isotopes were conducted to investigate the petrology, isotope geochemistry and the age of mineralized tonalities. U-Pb dating of LA-ICP-MS zircon was conducted to investigate the age of the sample, which is 421.8±2.5Ma, and the Re-Os weighted mean age for five molybde-nite samples is 409.1±2.6Ma, suggesting that, from the Late Silurian to the Early Devonian, the Layikeleke porphyry copper (molyb-denum) deposit was formed here, similar to things of the porphyry in Qiongheba area. The tonalities are of peraluminous and calc-al-kaline series with high Al₂O₃, CaO and low K₂O/Na₂O ratios. The pluton has low total REE content with relative enrichment of LREE and obscure Eu negative anomaly. The primitive mantle normalized trace element patterns are characterized by the depletion of the HFSE (Th, Nb, Ta, P, Ti) and enrichment of the LILE (Rb, Ba, U, K, Sr). The testing results of Hf isotope show that tonalitie plutons have high and positive ε_Hf(t) and younger model age, indicating that they were formed in a continental margin arc setting and were related to partial melting of subducted oceanic crust. The results obtained by the authors have important significance for deepen-ing the understanding of magmatic hydrothermal metallogenesis in this area.