【作者】 高红灿；

【导师】 郑荣才；

【作者基本信息】 成都理工大学 ， 沉积学， 2007， 博士

【摘要】 以四川盆地上三叠统须家河组为研究对象。首先，将四川盆地与松潘—甘孜褶皱带的构造演化都纳入特提斯构造域进行整体分析，认为川西坳陷为一个继松潘—甘孜大型周缘前陆盆地褶皱回返后，在其上所叠加发育的陆内前陆盆地，从而将四川前陆盆地的构造演化划分为三个阶段：早期周缘前陆盆地阶段(T_3m-T_3xt)、中期陆内前陆盆地阶段(T_3x²-J_3p)和晚期萎缩衰亡阶段（K₁-E₂）；其次，通过地层基准面旋回分析与对比，提出了四川盆地上三叠统“须家河组”和“香溪群”的对比方案，并依次相应于须二段—须六段将须家河组划分为5个长期旋回层序，每个长期旋回层序又进一步划分为3-4个中期旋回层序。在此基础上，以各长期和中期旋回层序的上升和下降半旋回相域为等时地层单元编制的四川盆地层序—岩相古地理图表明，须家河各时期的沉积相带展布严格受构造控制，从盆地边缘至中心依次发育冲积扇—扇三角洲—辫状河三角洲—浅湖沉积体系，形成以川中古隆起为中心，被川西前渊坳陷、川东北前渊坳陷和渝东-川东南克拉通坳陷半包围的“三坳围一隆”的沉积格局。最后，运用地质、测井和地震等学科相结合的技术方法对川西坳陷孝泉—新场—合兴场地区上三叠统须家河组四段砂体的分布进行了综合研究。另外，通过对四川盆地内不同类型的次级盆地的研究，得出前陆盆地和克拉通盆地不同的层序充填样式。①前陆盆地两侧具极不对称的层序地层充填样式。在盆缘冲断带一侧，随着造山带构造活动的增强，沉积物供给量与可容纳空间呈正比同步增大，但沉积物供给量总是大于至远大于新增的可容纳空间，从而以粗碎屑沉积为主。另外，由于其下切侵蚀作用强烈，其低位体系域相对发育，而高位体系域则因后期暴露剥蚀而保存不完整。在前隆斜坡带一侧，层序的充填样式主要受可容纳空间变化的影响，而可容纳空间的变化主要受盆缘冲断带构造活动远端效应的间接控制，其沉积物供给量则表现为与可容纳空间成反比变化的趋势，总体上以发育细碎屑沉积为主。由于其构造活动不强烈，河道下切侵蚀弱，故低位体系域不发育，而高位体系域相对发育。前陆盆地的沉积中心位于靠近冲断带一侧的前渊坳陷内。②克拉通盆地两侧表现为相似且对称的层序充填样式，低位体系域不发育，而湖侵和高位体系域均发育。其沉积中心位于克拉通坳陷的中部。③构造活动期以形成储层为主，而构造平静期以形成生油层和盖层为主。更多还原

【Abstract】 The Xujiahe Formation of Upper Triassic in Sichuan basin is mainly researchobjects of this thesis. First, by incorporating the tectonic evolution of Sichuan basinand Songpan-Ganzi fold belt into Tethyan tectonic domain for integral analysis, theconclusion is drawn that the western Sichuan depression was a intracontinentalforeland basin superimposing on Songpan-Ganzi peripheral foreland basin which hadfolded inversion before the Xujiahe Age of Late Triassic. As result, Sichuan forelandbasin is divided into three evolutionary phases - early peripheral foreland basin stage(T_3m-T_3t), middle intracontinental foreland basin stage (T_3x-J_3p) and late shrinking andextinct stage （K₁-E₂）.Second, according to the analysis of base-level cycles, a new correlation betweenXujiahe Formation and Xiangxi Group of Upper Triassic in Sichuan basin issuggested. At the same time, the Xujiahe Formation is divided into five long-termsequence cycles corresponding to the second member to the sixth member of XujiaheFormation, and Each long-term sequence cycle consists of 3-4 middle-term sequencecycles. By choosing the rising and falling base-level phases of each middle- andlong-period sequence cycle as the isochronous mapping unit, the sequencepaleogeography maps of Xujiahe Formation have been drawn in Sichuan basin, whichindicates that the sedimentary systems controlled strictly by tectonic pattern have acertain regularity: from basin margin to center - alluvial fan, fan delta, braidedstream-delta and shallow lake. Therefore, the distribution of sedimentary facies of theXujiahe Formation in Sichuan basin was characterized by "one paleouplifi surroundedby three depressions partially". "one paleouplift" was central Sichuan paleouplifl, and"three depressions" was West Sichuan foredeep depression, Northeast Sichuanfrredeep depression and East Chongqing-Southeast Sichuan craton depression.Finally, by applying the geologic, logging and seismic methods, amutiple-discipline comprehensive research on the distribution of sand bodies ofMember 4 of Xujiahe Formation has been done in Xiaoquan, Xinchang andHexingchang of West Sichuan depression.In addition, on the basis of the study on different subbasins in Sichuan basin, the different filling patterns of foreland basins and craton basins have been drawn.①The two sides of foreland basins take on asymmetric sequence filling patterns. On theside of foreland thrust belt, with intenseness of tectonic activity in orogenic belt, thesedimentary supply and accommodation show a tendency to increase in positiveproportion together. However, the sedimentary supply is （much） more thanaccommodation, and the grain size of the sediments is coarser. In addition, becausethe cutting erosion is strong on the side of foreland thrust belt, lowstand system tractdevelops relatively, but highstand system tract reserves incompletely by virtue of latedenudation. On the side of slope belt, the sequence filling patterns is mainlyinfluenced by the change of accommodation, which is controlled by distal effect ofthe thrusting event in basin margin indirectly. The sedimentary supply varies inreverse proportion to the accommodation. The grain size of the sediments is fine onthe side of slope belt. Because the tectonic activity and cutting erosion are not strongenough, lowstand system tract develops incompletely, but highstand system tractdevelops relatively. The depositional center of foreland basins locates in foredeepdepression closing to the side of foreland thrust belt.②The sequence filling patternsin two sides of craton basins are similarity and symmetry where lowstand system tractdevelops incompletely, but highstand system tract develops relatively. Thedepositional center of craton basins locates in the middle of craton depression.③The reservoirs of Sichuan basin formed during the tectonic active period, and thesource-cap rock formed during the tectonic inactive period.更多还原