新疆焉耆盆地中生代原始面貌探讨

Discussion on Primary Morphology of Yanqi Basin,Xinjiang in Mesozoic

新疆焉耆盆地是一中新生代盆地,通过对盆地残留中生代地层岩石特征分析,物源区位于盆地北部,碎屑由北向南搬运,在北部为粗碎屑堆积,南部为细碎屑堆积;盆地北部为辫状河相沉积,南部为滨浅湖相—辫状河相沉积;在盆地北部南天山山前和南部库鲁克塔格山上,现今仍残留有侏罗纪地层;这些都显示盆地原始沉积面貌比现今盆地要广。磷灰石裂变径迹数据显示焉耆盆地周邻山体于早白垩世中期隆升,早白垩世中期之前焉耆盆地与尤尔都斯、库车和库米什盆地在中生代是相连通的,为塔里木大型盆地的北部,晚白垩世大型盆地开始解体,焉耆盆地与这三个地区被分隔成彼此独立的盆地。

Yanqi Basin of Xinjiang is a Meso-cenozoic basin, through the lithological analysis on the residual Mesozoic formation of the basin, such conclusion is reached that the source area located in the north of the basin, the debris were transported from the north to the south, so the coarse fragment were deposited in the north while fine clastic in the south; The sedimentary facies in northern basin were braided stream facies while shore-shallow lacustrine stream facies in southern basin ; Concurrently, the Jurassic formation is still remained in front of Tianshan mountain of northern basin and on Kulukatag mountain of southern basin; All above show that the primary face of the basin is wider than the present one. On the basis of apatite fission track age, these Mountains began to lift in the middle of lower Crataceous. The four basins, Youedosi basin, Kuqa basin, Yanqi basin and Kumier basin, were coherent and formed the north of the larger Tarim basin before the time. The larger basin was disorganized in Late Crataceous, Yanqi basin and these basins were divided into four separate basins.