准噶尔盆地四棵树凹陷三叠系物源及其构造意义  

Triassic Provenance and Its Tectonic Significance in Sikeshu Sag, Junggar Basin

作　　者：朱文[1] 吴朝东[1,2] 王家林[1] 陈榕[1,2] 吴峻 周天琪[1,2] ZHU Wen;WU Chaodong;WANG Jialin;CHEN Rong;WU Jun;ZHOU Tianqi(Peking University,MOE Key Laboratory of Orogenic Belts and Crustal Evolution,Beijing 100871, China;Peking University,Institute of Oil and Gas, Beijing 100871, China)

机构地区：[1]北京大学造山带与地壳演化教育部重点实验室,北京100871 [2]北京大学石油与天然气研究中心,北京100871

出　　处：《新疆石油地质》2017年第5期512-518,共7页Xinjiang Petroleum Geology

基　　金：国家科技重大专项(2017ZX05008-001)

摘　　要：二叠纪—三叠纪是准噶尔盆地构造演化的关键时期,但对其构造演化的认识仍存在较多争议。以四棵树凹陷三叠系为研究对象,综合沉积环境、古流向、砾石成分、砂岩碎屑组分和碎屑锆石U-Pb年龄等,进行了物源分析,并探讨了准噶尔盆地南缘三叠纪的构造演化历史。综合分析认为,四棵树凹陷下三叠统上仓房沟群物源主要为北天山及中天山北缘造山带,南天山及中天山南缘为次要物源;而中—上三叠统小泉沟群物源则仅为北天山及中天山北缘。中—晚三叠世物源变化的主要原因是准噶尔盆地南缘发生了拗陷,导致沉积盆地沉降,四棵树凹陷开始形成,说明中—晚三叠世为准噶尔盆地南缘拗陷盆地演化的关键时期。Permian and Triassic are the key periods for tectonic evolution in Junggar basin,but there are lots of disputes on the understanding of the tectonic evolution.Aiming at Triassic series of Sikeshu sag,the paper performs provenance analysis by combining the data of sedimentary environment,paleocurrent direction,gravel composition,detrital component of sandstone and detrital zircon age of U-Pb,and discusses the tectonic evolution history of the southern margin of Junggar basin during Triassic period.The composite analysis shows that theorogenic belts of North Tianshan Mountains and the northern margin of the central Tianshan Mountains are the major provenances of the upper Cangfanggou group of the Lower Triassic in Sikeshu sag,and the South Tianshan Mountains and the southern margin of Central Tianshan Mountains are the minor provenances.The variations of the provenances during Middle-Late Triassic epochs can be attributed to thesubsidence of sedimentary basin resulted from the occurrence of depression in the southern margin of Junggar basin,which was the initiation of Sikeshu sag,indicating that Middle-Late Triassic epochs are the key periods for the down-wraped basin evolution in the southernmargin of Junggar basin.

关 键 词：准噶尔盆地 四棵树凹陷 三叠系 物源分析 构造意义 

分 类 号：TE111.1[石油与天然气工程—油气勘探]