Abstract:In order to discuss the petrogenesis, formation age, and tectonic setting of the newly discovered Kurganbas granite in the southern margin of Altay in the Mosekeaoyi area of Fuhai county, Xinjiang, U-Pb dating of rocks and geochemical studies of LA-ICP-MS zirconium were developed to investigated. The results show that the age of U-Pb zircon is 391.4 ± 4.0 Ma (MSWD = 0.96) and the age of formation is Middle Devonian. The Kurganbas granite is a high-potassium calcium-alkali weak peraluminous granite with a SiO2 content of 62.73%–74.75%, TiO2 content of 0.32%–0.90%, Na2O content of 3.06%–5.02%, K2O content of 3.37%–4.1%, P2O5 content of 0.01%–0.19% , and Al2O3 content is 12.38%–16.00%. With high silicon, high alkali, aluminum-rich, low titanium, and low phosphorus characteristics, trace elements show LREE enrichment and obvious fractionation, HREE loss, moderate Eu negative anomaly (δEu = 0.41 ～ 0.98), enrichment of Rb, Th, K, La, and the characteristic of loss of Ba, Nb, P, and Ti. It is supposed that the Kurganbass was formed in a volcanic island arc environment related to subduction and reduction, and is the product of the subduction of reduction of the Kazakhstan-Jungar plate to the Altay block. It provides new evidence for the tectonic evolution of the area.