Geochemical, zircon U-Pb dating and Hf isotope compositions studies for Tatelekebulake granite in South Altyn Tagh

Geochemical researches indicate that the monzogranite from Washixia area in the South of Altyn Tagh is rich in silica (SiO2 = 63 62% similar to 72 06%) and alkali (ALK = 6 39 similar to 7 83), and is peraluminous The rock has moderate REE concentration and negative Eu anomaly, showing the relative enrichment of LREE pattern, which is a typical high-K calc alkaline S type granite with the character of enrichment of LILE ( Rb, Th and U) and depletion of Nb, Ta, Sr, P and Ti All spots of zircons from the rock have epsilon(Hf) (t) = - 9 1 similar to -10 5 and t(DM)(C) = 1457 similar to 1553Ma, suggesting that the source rock of the granite is mainly from crust which was accreted in Mesoproterozoic The element ratios, such as Nb/Ta, Zr/Hf, Th/U, combining with the high CaO/Na2O and low Al2O3/TiO2, high Al2O3, CaO, FeOT + MgO + TIO2 and Y, Yb concentrations, indicate the rock is formed by the biotite partial melting of greywacke from middle to lower crust in the condition of lower pressure and higher temperature with plagioclase amphibolite as the residue Zircons from the granite are euhydral and preserve magmatic zones on the CL images Based on the CL images and the characters of trace element (Th/U >0 1) of zircons, LA-ICP-MS in situ U Pb dating obtains the age of 462 +/- 2Ma should be the formation age of the granite According to CaO/Na2O-Al2O3/TiO2 and R-1 R-2 diagram, the granite is formed in original period after collision Comparing the formation age (462Ma) with the metamorphic ages (similar to 500Ma) of South Altyn Tagh, the monzogranite from Washixia art a in Altyn Tagh is produced in the initial stage of stress relief after collision, when the crustal materials were partial melted due to the lessening of stress