The Recognition of Shengliqiao Rock Mass of Saliyakedaban, West Kunlun

With complex lithology and rock types, Shengliqiao rock mass is a large outcrop of mixed granite in Kudi-Mazha area of West Kunlun. Geochemical characteristics of high SiO₂ content indicates that the rock mass is mainly acid rock. The value of Rittmann index(σ) is between 2.13 and 2.89; strong incompatible elements including K, U, Ba, Rb, Th have obvious enrichment features; high field elements such as Nb, Ta, P, Ti are apparently depleted; the distribution of Nb-Ta is in a groove shape, and Sr element is also in an obvious deficit; the total of rare earth element is fairly low, with LREE enriched while HREE depleted. According to the zircon U-Pb isotopic dating analysis, the average ages are (229.7±1.4)Ma and (204.65±0.59)Ma, indicating that Shengliqiao rock mass occurred in the Late Triassic age. In summary, the rock is I-type granite of high aluminum potassium calcium alkaline, a result of interaction between crust and mantle. The material resource came mainly from the mantle with a certain amount of crustal material. Combined with the features of regional tectonic position and magmatic evolution of the analysis, it is concluded that Shengliqiao rock unit is a product of intracontinental subduction. The displayed feature of island arc granite is induced by the influence of crustal material resources.