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综合露头、测钻井资料的对比,建立了塔里木盆地西南坳陷南天山和西昆仑山前带白垩系层序地层格架。依据区域性不整合面和区域性沉积相突变界面将研究区白垩系划分为2个二级层序;依据沉积相变化、地层叠加样式的转换面以及沉积旋回结构划分出4个三级层序。通过区域内野外露头和单井等资料的分析,共识别了冲积扇、辫状河、曲流河、辫状河三角洲及曲流河三角洲等5种主要沉积相。系统地编制了各层序的沉积体系展布图,揭示了沉积体系的空间展布及纵向演化。研究表明,白垩纪塔里木盆地西南坳陷沉积范围和沉积体系有明显变化。沉积范围先由山前带向盆内扩展,反映了研究区整体上发生了较大规模的海进事件。沉积体系的演化整体上表现为陆相—海相沉积的变化过程。
Based on the comparison of outcrop and measured drilling data, the Cretaceous sequence stratigraphic framework of the southern Tianshan and Western Kunlun piedmont forerocks in the southwest depression of the Tarim Basin was established. The Cretaceous in the study area is divided into two second-order sequences according to the regional unconformity and the regional facies-facies abrupt change interface. According to the sedimentary facies change, the stratigraphic superimposed pattern conversion surface and the sedimentary cycle structure, four third-order sequences . Through the analysis of outcrops and single wells in the area, five major sedimentary facies such as alluvial fan, braided river, meandering river, braided river delta and meandering river delta are identified. Systematic preparation of the sedimentary system map of the various sequences revealed the spatial distribution of the sedimentary system and the longitudinal evolution. The study shows that the Cretaceous Tarim Basin, southwest depression sedimentary system and sedimentary system has changed significantly. The depositional range first extends from the piedmont zone to the basin, reflecting a large-scale marine intrusion event in the study area as a whole. The evolution of sedimentary system as a whole shows the change of continental facies-marine sediment.