中文摘要：

卡拉麦里缝合带是北疆的一条重要界线,沿该带广泛发育晚古生代火山岩。这些火山岩具有LILE相对富集、HFSE相对亏损的特征,且具有较高的Nb、Zr、TiO2含量和Zr/Y、Nb/Y比值,Sr-Nd同位素主要表现出亏损的特征。综合分析表明,这些火山岩形成于后碰撞期。对卡拉麦里缝合带而言,从西向东后碰撞火山岩的时代逐渐变新,表明该缝合带从西向东逐渐演化进入后碰撞期,这从侧面反映了卡拉麦里洋盆是从西向东逐渐关闭的。对卡拉麦里缝合带而言,在后碰撞期,岩石圈伸展减薄,软流圈地幔物质上涌并发生部分熔融,加上地幔对流作用强烈,使得缝合带下产生了大规模的幔源岩浆底垫;先前在洋壳消减期被流体交代提取过的岩石圈地幔也在低压高温下发生部分熔融,形成的熔体混染了底垫的软流圈物质并喷发,形成了晚古生代的后碰撞期火山岩。

英文摘要：

Kalamaili suture zone is an important plate boundary in north Xinjiang, and there are plenty of Neopaleozoic volcanic rocks around it. These volcanic rocks are enriched in LILEs and relatively depleted in HF- SEs, and they are also characterized by high Nb, Zr, TiO2 contents and Zr/Y, Nb/Y ratios, and depleted SrNd isotopes. The characteristics of these volcanic rocks suggest that they were produced in post-collisional period. The post-collisional volcanic rocks around Kalamaili suture zone become younger from west to east, which indicates that this suture zone entered post-collisional period gradually from west to east, and reflects that the Kalamaili Ocean had been closed gradually from west to east. As to the Kalamaili suture zone in post-collisional period, the lithosphere extended and thinned, and the asthenosphere materials upwelled and melted partially, and intensive mantle convection occurred, leading to a plenty of mantle-derived magmas underplating the suture zone. The litbospheric mantle metasomatized by fluid in subduction period melted partially under decompression and high temperature, the resulting melts contaminated the underplating asthenospheric materials, and the erupted lavas became the Neopaleozoic post-collisional volcanic rocks.