川西前陆盆地须家河组沉积相及岩相古地理演化

川西前陆盆地上三叠统须家河组是油气勘探的重点层位.依据新的地层划分方案、大量钻井、露头及岩芯资料,结合区域地质特征,详细研究了须家河组沉积相、岩相古地理特征及其演化.结果表明:研究区内主要发育了冲积扇、湖相三角洲、湖泊、海相三角洲、滨岸和海湾六种主要的沉积相类型;古地理演化经历了由海相环境-海陆过渡相环境-陆相环境的转变;在须四早期,受安县运动的影响,龙门山褶皱成山,使研究区与阿坝海域完全隔绝,整个四川盆地真正进入了陆相沉积环境.

Sedimentary facies and litho-paleogeographic evolution of the Upper Triassic Xujiahe Formation in West Sichuan foreland basin

Based on the new stratigraphic division draft and large quantities of drilling, outcrop and core data, the authors have studied in detail sedimentary facies, paleogeographic characteristics and evolution of the Upper Triassic Xujiahe Formation in West Sichuan foreland basin. The conclusions show that Xujiahe Formation mainly deposited on alluvial fans, lacustrine deltas, lacustrine facies, marine deltas facies, shoreline facies and bay facies. According to studied in detail sedimentary facies and the characteristics of the tectonic evolution in the Xujiahe period, the authors think that the paleogeography evolved from marine environment, paralic environment to continental environment in the studied zone. Furthermore, with Anxian Movement influencing, Longmenshan uplifted and became a mountain which made the studied zone isolated with Ganzi sea and became a forland basin.