中天山地块是天山造山带的重要组成部分，其前寒武纪基底的年龄自西向东逐渐变老。星星峡群位于中天山地块最东端，是天山造山带最古老的前寒武纪基底。目前为止，有关星星峡群原岩形成的构造背景与后期发生的变形变质作用尚无详细研究。文章重点对星星峡群的变质片岩和片麻岩进行了野外观察和取样，室内开展了薄片观察、矿物电子探针分析以及全岩地球化学测试。全岩主量元素地球化学分析表明，星星峡群变质片岩和片麻岩的原岩主要为泥质岩和砂岩；微量与稀土元素结果显示，星星峡群沉积形成于大陆弧或活动大陆边缘环境。依据矿物电子探针成分分析数据结合全岩主量元素测试结果计算获得，星星峡群所经历的峰期变质温压条件大致为610~730℃，6.8~8.5 kbar。此外，通过最新的基底岩石变质年龄限定星星峡群发生峰期变质的时间大概在380 Ma。

The Central Tiansan Block is an important part of the Chinese Tianshan Orogenic Belt, and the formation age of Precambrian basement in the Central Tianshan Block becomes older as it goes east. The Xingxingxia Group is located in the easternmost of the Central Tianshan Block and has the oldest Precambrian basement of the Chinese Tianshan Orogen. In this paper, the metamorphic schist and gneiss in the Xingxingxia Group were observed and sampled in the field, and thin section observation, mineral electron probe analysis and whole-rock geochemistry test were carried out in the laboratory. The geochemical analysis of the whole rock major element indicates that the protoliths of the metamorphic schist and gneiss in the Xingxingxia Group are mainly argillaceous rocks and sandstone. The results of trace elements and REE indicate that the Xingxingxia Group was deposited in continental arc or active continental margin environment based on the results of EPMA and major elements. The temperature and pressure conditions of the peak metamorphism of the Xingxingxia Group were 610-730℃ and 6.8-8.5 kbar. In addition, according to the latest metamorphic age of the basement rock, the time of peak metamorphism of the Xingxingxia Group is about 380 Ma.