2. 西北政法大学军民融合发展研究院，西安710122;

3. 中国地质调查局乌鲁木齐自然资源综合调查中心，乌鲁木齐830057

段。察哈乌苏侵入体处在阿拉套山的西段，侵位于上泥盆统托斯库尔他乌组碎屑岩中，岩性以二长花

岗岩为主，少量钾长花岗岩。LA--ICP--MS 锆石U--Pb 测年结果和Hf 同位素组成表明察哈乌苏岩体二

长花岗岩的206Pb /238U 加权平均年龄为( 312. 7 ± 3. 6) Ma，岩体的形成时代属于晚石炭世初期阶段，岩浆可能来自亏损地幔的部分熔融，演化过程中遭受了地壳物质混染，可能为同碰撞挤压向后碰撞伸展转换阶段、张性构造环境下岩浆活动的产物。

2. Military-civilian Integration Development Ｒesearch Institute，Northwest University of Political Science and Law，

Xi'an 710122，China;

3. Center of Urumqi Natural Ｒesources Comprehensive Survey，CGS，Urumqi 830057，China

MS zircon U--Pb dating results and Hf isotopic compositions show that the 206Pb /238U weighted average age of the monzogranite is ( 312. 7 ± 3. 6) Ma，indicating the Chahawusu pluton was emplaced at the early stage of Late Carboniferous．The primary magma was likely derived from partial melting of a depleted mantle and was then contaminated by crustal materials during magma evolution processes． The Chahawusu pluton may be the product of magma activities under the extensional tectonic environment in the transitional stage from syn-collision compression to postcollision

extension．