四川盆地的上三迭统,是一套以陆相为主的兼有海相、海陆交互相碎屑岩沉积。岩性、岩相变化较大,缺乏区域性标志层。上三迭统内部的地壳运动界面(简称运动面,下同),常被特有的底冲刷现象所混淆和掩盖。以 Clathropteris—Dictyophyllum 为代表的植物化石组合,自下而上分异不甚明显,而赖以建组划段的菊石、海相瓣鳃类的 The Upper Triassic in the Sichuan Basin is a suite of marine-facies, marine-continental interaction clastic sediments dominated by continental facies. Lithology, facies changes larger, the lack of regional signs layer. The crustal movement interface (referred to as the moving surface, the same below) within the Upper Triassic is often confused and covered by the unique bottom flushing phenomenon. The fossil assemblage represented by Clathropteris-Dictyophyllum is not very distinct from the bottom up, but the ammoniferous,