通过地表露头和钻井岩心的观察,以及测井曲线和地震剖面的综合分析,对分割川西前陆盆地侏罗系陆相碎屑岩充填实体的层序界面进行了识别和追踪,将该区层序界面划分为两种类型:不整合面及侵蚀沉积间断面和最大湖泛面,据此在全盆侏罗系地层中识别出13个层序界面,将川西前陆盆地侏罗系划分为13个三级层序。据盆地沉积特征,自西向东选择一些有代表性的层序剖面,进行盆地内不同相带间的层序对比,建立了研究区侏罗纪等时层序地层格架。并在川西前陆盆地侏罗系中识别出4种沉积体系:冲(洪)积、湖泊、扇三角洲、三角洲沉积体系。并在层序格架中讨论了各沉积体系的横向展布,大体是从盆地西缘到东缘为冲积扇—冲积平原、三角洲平原—三角洲前缘—湖底扇—滨浅湖—半深湖—三角洲—曲流河的展布方式。其中冲积扇和冲积平原分布范围相对较小,而三角洲—滨浅湖分布范围广阔,且三角洲与浅湖相在垂向上频繁交替。
Based on observing surface outcrops and drilling cores,comprehensive analysis well logs and seismic profiles,sequence interface was identified and tracked which break up Jurassic continental facies clastic rock filling entities in the western Sichuan foreland basin,and sequence interface was divided into two types in this area: unconformity and erosion sediment discontinuity and max flood surface(MFS),13 sequence boundaries identified in the whole basin of Jurassic strata,as well as the western Sichuan foreland basin Jurassic is divided into 13 sedimentary sequences.According to sedimentary characteristics of basin,from west to east,selecting of some representative sequence profiles,in order to sequence correlation between different facies tract in this basin,and set up Jurassic sequence stratigraphic framework.And then four kinds of depositional systems were identified in the western Sichuan foreland basin Jurassic: alluvion(diluvial),lakes,fan delta,delta depositional system,and so on.And it is discussed that the horizontal distribution of depositional system under sequence stratigraphic framework.Generally,from the west margin to the east margin of the basin,the distribution ways are the alluvial fan-the alluvial plain,delta plain-delta front-sublacustrine fan-shore and shallow lake semi deep lake-delta-meandering river.The range of the alluvial fan and alluvial plain is relatively small,and the distribution of delta-shore and shallow lake is wide-ranging,and the delta and shallow lake frequent at the turn in vertical.