Abstract: The foreland basin in western margin of Ordos Basin experienced the Indo-China movement and the Yanshan movement from early stage of the Late Triassic period to the Middle Jurassic period. During those periods, the western margin was wholly uplifted and orogenic belts appeared in the southwest and northwest. The successive palaeogeographic framework shows that the south part of western margin was lacustrine environment and fluvial environment in the north. The sedimentary facies changed from littoral facies to lacustrine and swamp facies, which was resulted from the forming of Qinling orogenic belt. The foreland basin was formed from Late Jurassic to Early Cretaceous period by strongly thrusting and overriding during the Yanshan movement. There develop angular unconformities in this area. The deposition record indicates the foreland basin framework which is represented by uplifts alternating with depressions. The conclusion is obviously different from that the foreland basin formed in Late Triassic period. The fact that the foreland basin was rebuilt by the Himalaya movement from the Late Cretaceous to Cenozoic period, together with developed angular unconformities and deposition record responses, demonstrates the plain-swamp sedimentary environment.

Key words: Ordos Basin, western wargin, foreland basin, tectonic, sedimentary