鄂尔多斯盆地上三叠世构造活动对沉积相类型的控制

Triassic in ordos basin tectonic activities to control the types of sedimentary facies

鄂尔多斯盆地位于华北板块的西部,长期以来上三叠统延长组是本区的主要油气勘探目的层。本文在收集前人对研究区沉积相研究资料基础上,以及对盆地周边露头剖面观察之后,发现整个延长组的沉积过程受到了印支运动旋回的控制。构造活动引起盆地基底整体升降,以及沉积中心的迁移,使得盆地不同地区同一时期或者同一地区不同时期发育了不同的沉积相。其中,延长组早期盆地基底整体下降为主,主要发育河流相,三角洲相,滨浅湖相;延长组中期经历了一次比较大的构造活动,湖泊面积变广,同时发育有重力流沉积。延长组后期基底地层整体以抬升为主,局部地区发生剥蚀,主要发育河流,三角洲沉积。

The Ordos Basin is located in the west of the North China plate,and the upper Triassic formation is the main oil and gas exploration target in the region for a long time.Based on the collection of previous studies of sedimentary facies research based on the data,and after the observation of outcrops around the basin,found that the Yanchang Formation in the deposition process was controlled by the Indosinian movement cycle.Tectonic activity causes the whole basin basement to rise and fall,as well as the migration of the sedimentary center,so that different sedimentary facies have been developed in different regions of the basin during the same period or the same area in different periods.The Yanchang Formation in early fall basement overall,mainly developed fluvial facies,delta facies,shore shallow lake facies;middle Yanchang group experienced a relatively large tectonic activity,the lake area became wide,also developed gravity flow deposits.In the late stage of the formation of the late formation of the basal strata,the overall uplift is the main part,and the erosion occurs in the local area.