Owing to continent -continent collision along the Dabie-Jiaonan orogenic belt between the North China and Yangtze plates, the Yangtze plate south of the orogenic belt became a foreland deformation belt, and a foreland basin along the Yangtze River was developed on the foreland belt. The foreland basin firstly appeared in a depression region which remained in the Lower Yangtze region during retrogression. The foreland basin became a double - pressioned basin probably controlled by back thrusting along the Chuhe and Jiangnan boundary faults in the Huangmaqin period (T3). During deposition of the lower Xiangshan Group (J1), intense uplift of the Jiangnan uplift belt perhaps made the foreland basin migrate toward the north. During deposition of the lower Xiangshan Group (J1), the foreland basin shrank and became small separated basins before disappearance of the foreland basin. Angular unconformities between the Huangmaqin Group (T3h) and underlying strata, the Xiangshan (J1-2x) and Huangmaqin (T3h) groups as well as the Xiangshan Group (J1-2x) and overlying strata represent three intense compression deformation, and also possibly reflect three intense collision between the North China and Yangtze plates.