Abstract:The Reshui area is located in Doulan county, eastern section of the East Kunlun orogenic belt. There are a large number of granitic rock combinations. The main rock types are monzogranite and granodiorite. This paper reports on the geochemical and LA-ICP-MS zircon U-Pb dating results of monzogranite and granitic in Reshui area, the results provide new informations for establish a complete chronological framework and tectonic evolution. The zircon U-Pb isotope dating study shows that the crystallization ages of the monzogranite and granodiorite are 232.4±1.3 Ma and 230.8±1.1 Ma, which is the product of granitic magmatism during Middle Triassic. The characteristics of rock and geochemistry indicate that the monzogranite and granodiorite are high-potassium-calcium-alkaline I-type granites, with high K2O content (2.2%~4.74%); aluminum saturation index A/CNK values are both less than 1.1, showing quasi-aluminum characteristics; there is a significant negative correlation between P2O5 and SiO2, and also exhibits enrichment of light rare earth elements and large ion lithophile elements (such as K, Rb, La), loss of heavy rare earth elements and high field strength elements (such as Nb, Ta, Ti, P), and Eu negative anomalies. Combined with the previous regional geological researchs, we believe that the granitic rock combinations in Reshui area is formed the partial melting of the lower crust that effected by the underplating of mantle-derived magma, The mantle-derived magma and the crustal-derived magma are mixed in different proportions, and during the magma evolution occurred fractional crystallization. Animaqing ocean subducted to the east Kunlun plate in Late Permian, Reshui area was still in the volcanic arc environment produced by the subduction of the oceanic crust until to Middle Triassic, The monzonitic and granitic diorite are typical products in this stage.