CAJ | 학술논문

提西天山伊犁地区广泛出露的大哈拉军山组火山-沉积岩系，是研究西天山早石炭世古地理格局和天山古生代造山作用演化过程最为直接的载体。文章对西天山乌孙山地区大哈拉军山组砂岩样品进行了LA-ICP-MS锆石U-Pb测年。结果显示，其碎屑锆石206Pb/238U表面年龄分布范围较宽（(321±2)~(435±2) Ma），按年龄及频率分布特征大致可以划分为2组：321~372 Ma和395~435 Ma。结合锆石的矿物学特征、CL图像特点及乌孙山区域地质资料，初步获得以下认识：(1)西天山乌孙山地区大哈拉军山组沉积时代不晚于早石炭世晚期；(2)所研究砂岩的碎屑物质主要来源于乌孙山及南部那拉提山相关的火山岩浆岩；(3)西天山造山带在中—晚泥盆世期间经历了一次重要的洋陆转换事件。早石炭世以后，进入后碰撞裂谷伸展演化阶段，因此大哈拉军山组火山-沉积岩系形成后碰撞伸展构造环境。
제서천산이리지구엄범출로적대합랍군산조화산-침적암계，시연구서천산조석탄세고지리격국화천산고생대조산작용연화과정최위직접적재체。문장대서천산오손산지구대합랍군산조사암양품진행료LA-ICP-MS고석U-Pb측년。결과현시，기쇄설고석206Pb/238U표면년령분포범위교관（(321±2)~(435±2) Ma），안년령급빈솔분포특정대치가이화분위2조：321~372 Ma화395~435 Ma。결합고석적광물학특정、CL도상특점급오손산구역지질자료，초보획득이하인식：(1)서천산오손산지구대합랍군산조침적시대불만우조석탄세만기；(2)소연구사암적쇄설물질주요래원우오손산급남부나랍제산상관적화산암장암；(3)서천산조산대재중—만니분세기간경력료일차중요적양륙전환사건。조석탄세이후，진입후팽당렬곡신전연화계단，인차대합랍군산조화산-침적암계형성후팽당신전구조배경。
Dahalajunshan Formation volcanic-sedimentary rocks, widespread in Yili area, western Tianshan, are the most direct carrier in the study of Early Carboniferous palaeogeography of western Tianshan and Paleozoic orogenic evolution of the Tianshan. The age distribution of detrital zircons of sandstone in Dahalajunshan Formation was studied by using LA-ICP-MS U-Pb isotopic ages of zircons. The results show that the detrital zircons have a wide range of zircon ages from (321±2) Ma to (435±2) Ma, which <br> can be divided into 2 groups:321-372 Ma and 395-435 Ma, according to the age and frequency distribution characteristics. Based on these dating data, combined with the mineralogical characteristics and CL images of zircons as well as the regional geological data of the Wusun Mountain, the authors have reached the following conclusions:(1) The age of the deposition of Dahalajunshan Formation is not later than the later Early Carboniferous;(2) the detrital materials of the studied sandstone were mainly derived from volcanic and magmatic rocks related to the Wusun Mountain and Nalati Mountain; (3) during middle-late Devonian, western Tianshan orogenic belt experienced significant ocean-land transition events and entered into the post-collision rift extensional stage. Therefore, the formation of volcanic-sedimentary rocks of Dahalajunshan Formation was in a post-collision extensional setting.