Yanshanian tectonic movement was very common in west-central China. Firstly

it appears as the unconformity between Cretaceous and Jurassic

and even the Tertiary directly and unconformably contact with Jurassic. Secondly

Yanshanian palaeostructures occur in every basin in west-central China. Thirdly

Lasha and Qiangtang terrains collided along Bangonghu-Nujiang suture zone

leading to the uplift of earth crust

a set of red molasse formation was deposited both in Qiangtang basin and Lasha terrain. As a result

an apparent angular unconformity occurs between Cretaceous and Jurassic. Yanshanian tectonic movement is characterized by the followings:regional tectonic elevation led to the shrinkage of sedimentary basin and relatively weak tectonic deformation; large set of coarse glutenite deposits were commonly developed in the front-edge of orogenic belt; magmatic activity occurred in local area within the orogenic belt. The significances of Yanshanian tectonic movement to hydrocarbon accumulation include:(1) Speed up of the thermal evolution of source rocks made the two major coal measure source rocks

Upper Paleozoic and Upper Triassic-Lower and Middle Jurassic

in west-central China entering the peaks of hydrocarbon generation and expulsion or began to generate hydrocarbons respectively in Late Yanshanian; (2) The timing of Yanshanian palaeostructures and hydrocarbon generation and expulsion of source rocks would be favorable for early accumulation of hydrocarbons; (3) Readjustment of oil and gas by Himalayanian tectonic movement would be favorable for the formation of secondary oil and gas pools in new traps near the Yanshanian fossil oil and gas reservoirs; (4) Yanshanian tectonic elevation led to the development of good reservoirs of coarse clastic rocks deposited in low water level system tract

thus they would be favorable for reservoiring of oil and gas.