【摘要】 龙门山位于中国地质构造东、西交界部位,印支期褶皱冲断成山后,由于燕山期、喜山期的构造叠加、改造和掩盖,印支龙门山的原貌难以恢复,因而存在认识上的分歧。为澄清该问题,依照盆山耦合规律,侧重研究了四川盆地内的钻井、地震资料,结合山区构造形迹及其演化规律,再次探讨了印支龙门山的形成和发展及其与四川盆地油气成藏的关系。结论认为:①须下盆沉积物源与印支早期活动有关,印支早幕秦岭缝合隆升,提供物源在包括与泸州古隆起所夹海滨堆积,诺利期末,松潘—甘孜地区南、北两侧古特提斯洋先后封闭、缝合,极其强烈对冲挤压产生的合力推向稳定陆块边缘形成龙门山逆冲推覆带;②安县运动褶皱冲断形成巍峨高耸的龙门山,该运动是龙门山印支期的主要造山幕;③须上盆具规模宏大的磨拉石冲积扇联扇体系,并表现为北强南弱的活动特征;④造山运动后经历了较长的构造稳定期,以剥蚀夷平和缓慢湖进沉积为主,侏罗纪前不存在"印支末期运动";⑤须上盆、须下盆是两个性质不同且"反扣"的盆地,各自控制其油气成藏的有利领域,其中须下盆以陆缘转变后的川西坳陷为主,须上盆则以盆中湖沼及入湖河流砂体配置条件为主。更多还原

【Abstract】 The Longmen Shan Mountain is situated at the boundary area between the eastern and western geological structure of the Chinese continent.Since this mountain came into being from the Indosinian folds and thrusts,its original geography has been difficult to recover due to the structural superposition,reformation and concealment during the Yanshan and Himalayan Epoch.According to the basin-mountain coupling rule,this paper particularly reviews drilling and seismic data in the Sichuan Basin,then in combination with the features and evolution laws of the mountainous structure,discusses again the formation and development of the Longmen Shan Thrust-Nappe Structure in the Indosinian Movement and their relationship with oil and gas pooling in the Sichuan Basin.The following conclusions are drawn.(1) The sedimentary sources in the "Late Xujiahe" basin formation period are closely related to the earlier Indosinian movement;the Paleo-Tethys Ocean in the north and south wings of the Songpan-Ganzi area was first sealed then closed,and was pushed to the margin of the steady continent by the significantly combined force of hedging and thrusting.(2) The Longmen Shan Mountain was lifted up high and erected at the fold-and-thrust belt after the Anxian Movement,which was the main orphanse in the Longmen Shan Indosinian Epoch.(3) The crosslinking molasse alluvial fan system on an extremely large scale in the "Early Xujiahe" basin formation period shows its characteristics of "being strong in the north and weak in the south".(4) After the orogenic movement,the Longmen Shan Mountain experienced a rather long period of structural stability,and later was dominated by denudation,planation,and slow and gradual lake deposits,and no late-period Indosinian movement ever occurred before the Jurassic.(5) There were two totally different and inverted basins formed respectively in the "Early and Late Xujiahe" basin formation periods,where the favorable domains for hydrocarbon pooling were reserved: the West Sichuan(Chuanxi) Depression transformed from the continental margin dominates in the "Early Xujiahe" basin while sandbodies in the river marsh and lake march and inflow rivers dominate in the "Late Xujiahe" basin.更多还原