STUDY OF POSITIVE INVERSION STRUCTURES IN THE NORTH DEPRESSION OF THE SOUTH YELLOW SEA BASIN

Several types of positive inversion structures are developed in the Cenozoic strata of the Northeast Sag,North Sag,Middle Sag and South Sag in the North Depression of the South Yellow Sea Basin,including penetrated fault-propagation type,compressive fold type,reversed fault type,and so on.Oligocene and the end of Pliocene are the two main inversion periods,and the structural inversion in Oligocene is more obvious.The convergence rate between the Pacific Plate and Eurasia Plate is an important factor controlling the development of inversion structures in Cenozoic in the North Depression of the South Yellow Sea Basin.The positive inversion structures are favorable to hydrocarbon accumulation and unfavorable to hydrocarbon preservation if the intensity of tectonic inversion is great.