研究区位于西拉木伦河缝合带北侧,地理位置位于内蒙古东部草原区、大兴安岭南段,构造部位介于苏尼特左旗-锡林浩特-西乌珠穆沁旗南缝合线和西拉木伦河缝合带之间,是讨论华北地块北缘与其北侧地块拼贴过程的关键地区.通过对西拉木伦河缝合带北侧克什克腾旗(简称克旗)和林西地区二叠纪砂岩进行碎屑锆石LA-ICP-MS U-Pb年代学研究,认为克旗地区原中二叠世“哲斯组”可能为一套晚二叠世甚至早三叠世沉积.克旗、林西地区二叠纪的沉积物源主要来自其北侧的苏尼特左旗-锡林浩特-西乌旗南的岩浆弧,并有华北板块北缘物源混入,华北板块北缘与其北侧地块应在晚二叠世林西组沉积时期已经开始碰撞,导致林西地区林西组沉积具有南北两侧混合物源特征,板块碰撞的最终闭合的时间应在250 Ma左右. The study area is located on the north side of the West Lamelung River suture zone and is located in the grassland area of ​​eastern Inner Mongolia and the southern section of the Greater Hinggan Mountains. The study area lies between the Sunit Zuoqi-Xilinhot-West Ujimqin South Suture and Xilu Mu It is a key area to discuss the collage process between the north margin of North China block and the northern part of the Lunhe suture zone.Through the study on the relationship between the Keshiketeng Banner (referred to as Keqi) and Linxi According to the LA-ICP-MS U-Pb chronological study of detrital zircons in the Permian sandstones in the area, it is considered that the Middle-Permian Permian Group in the Keqi area may be a set of Late Permian- The sediments of Permian in Keqi and Linxi mainly come from the magmatic arc of Sunite Zuoqi-Xilinhot-Xiyuqi South of the north side, and are mixed with the source of the northern margin of North China Plate, while the North China Plate The north margin and the north side of the block should have collided during the deposition of the Late Permian Linxi Formation, causing the deposition of the Linxi Formation in the western part of the Linxi area to be characterized by mixture sources on both sides of the north and south. The closing time of the plate collision should be around 250 Ma .