关键词: 地层学效应, 沉积盆地格局演变, 印支运动, 晚三叠世, 中上扬子区

Abstract:

  The IndoChina movement occurred in the late Triassic led to the end of the Yangtze Platform that is characterized by a stable palaeogeographic element from the Edicaran to the end of the middle Triassic with deposition of shallowwater carbonates during much of this time. This geological event was genetically controlled by the extensively orogenic uplift and the strong southward crumpling of the NorthChina Plate. Together with the action of both the northward crumpling of the IndoChina Plate and the northwestward crumpling of the Huaxia Massif, a particular evolutionary succession of sedimentary basins from the residual marine basin to the continental molasse basin with the nature of the foreland basin was formed on the relatively stable base that is marked by the “Yangtze Platform”. Further, there was a parallelism in time between this particular succession of sedimentary basins and the forming and ending process of the foreland turbidity basin in the late Triassic on the Ruoergai Massif before the middle Triassic in the western part of Sichuan Province. Therefore, a systematic description on the stratigraphic impact of the IndoChina Movement and the evolutionary pattern of sedimentary basins of the late Triassic in the middleupper Yangtze Region can provide an important clue to peek the death of the PalaeoTethyan Sea, and also provide a thinking approach to resurvey a pseudomorph of the “Chuanxi Foreland Basin” that was genetically formed by the orogenic uplift of the Longmen Mountains orogenic belt, because the “Chuanxi Foreland Basin” has been used as the typical representation of the foreland basin for a long time.

Key words: stratigraphic forcing, evolution of sediementarybasin patterns, the Indochina movement, late Triassic, the middle upper Yangtze Region