【作者】 曾熠；

【导师】 陈洪德；

【作者基本信息】 成都理工大学 ， 构造地质学， 2011， 硕士

【摘要】 论文以沉积学，层序地层学，构造地质学，地球物理学等学科理论为指导，通过对川西前陆盆地中侏罗统沙溪庙组野外露头，钻井岩心，测井资料以及前人成果的综合分析，研究了川西前陆盆地中侏罗统上沙溪庙组的沉积体系特征，层序地层学特征，在此基础上进一步分析了川西前陆盆地上沙溪庙组沉积相带分布规律及砂体展布特征。根据岩石组合、沉积组构、沉积序列以及沉积机理等因素，并综合运用前人已有工作成果，本文认为川西前陆盆地上沙溪庙组主要发育大陆沉积体系组，包括冲积扇沉积体系、河流沉积体系，湖泊三角洲沉积体系和湖泊沉积体系。通过野外露头与钻井岩心观测，结合测井分析，川西前陆盆地上沙溪庙组层序的底界面主要表现为岩性岩相转换面；顶界面为上侏罗统遂宁组与中侏罗统上沙溪庙组的分界面，识别出上沙溪庙组发育一个三级层序。通过沉积物平面变化，碎屑成分分析，石英颗粒成因类型，古流向分析及重矿物分析对川西前陆盆地上沙溪庙组进行了物源分析，发现研究区存在盆地西缘龙门山逆冲推覆带及北缘米仓山－大巴山逆冲推覆带两个物源。通过分析盆地内沉积相带分布规律研究了其砂体展布特征，发现龙门山及米仓山－大巴山逆冲推覆带的构造运动沉积相带分布的主控因素，而砂体展布特征则完全受控于沉积相带的分布。并在研究层序发育短期基准面旋回的基础上，分析了砂体结构特征，发现盆缘造山带构造运动引起的可容纳空间变化机制通过控制短期基准面升降过程，控制了川西前陆盆地侏罗纪上沙溪庙地层中砂体结构、成因类型及发育规模。更多还原

【Abstract】 Guided by sedimentology, sequence stratigraphy, structural geology, geophysics and soon, Integrated researched the outcrops, cores ,logging data from the Middle Jurassic upperShaximiao formation in the western Sichuan foreland Basin, realized the charaters ofdepositional system, sequence stratigraphy, discussion the dis-tribution of sedimentaryfacies and the characteristics of sand body distribution.According to the petrofabric, depositional fabric , sedimentary sequence, life assemblageand so on, combined with predecessor’s research,Continental sedimentary system groupcontain alluvial fan sedimentary system, fluvial sedimentary system and lake sedimentarysystem were recognized in the western Sichuan foreland Basin.According to the outcrops and cores ,combined with logging data , the bottom surfaces ofsequence in upper Shaximiao formation in western sichuan foreland Basin mainly astransition surface of rock character and facies，the top surfaces of sequence were the interfaceof Suining formation and upper Shaximiao formation.one sedimentary sequence wererecognized in upper Shaximiao formation.According to the sediment level change，clastic component analysis，genetic types ofquartz grains，paleocurrent analysis and heavy mineral analysis，conducted the sourcs analysisof Middle Jurassic upper Shaximiao formation in western sichuan foreland Basin.Found outthere were tow sources of western sichuan fore-land Basin：Longmenshan thrust belt inwestern margin of basin and Micangshan-Dabashan thrust belt in northern margin of basin.According to discussion the distribution of sedimentary facies in the basin，re-searchedthe characteristics of sand body distribution. Found out that the tectonic movement ofLongmenshan thrust belt and Micangshan-Dabashan thrust belt were the top management of the distribution of sedimentary facies，and the characteristics of sand body distribution fullycontrolled by he distribution of sedimentary facies.And according to discussion sequencedevelopment short-term base level cycle，analyzied the structural characteristics of sandbody，found out the tectonic movement of orogenisc belt in the basin margin caused thechange in accommodation space control mechanism of the process of short-term base-levelmovements controlling the structural characteristics of sand body，genetic type and thedevelopment scale of Middle Jurassic upper Shaximiao formation in western sichuan forelandBasin.更多还原