The geomorphology map of Songliao basin

The Songliao Basin is a large Mesozoic and Cenozoic sedimentary basin in northeastern China, spanning Heilongjiang Province, Jilin Province, Liaoning Province and Inner Mongolia Autonomous Region. In the Asian stratigraphic division, it is at the intersection of the North Asian Intercontinental Zone and the Pacific Rim Territorial Zone. The Cretaceous period is the main stage of basin development. It has deposited non-marine volcanic rocks, volcanic clastic rocks, normal river facies, lacustrine facies and marsh fractal strata with a thickness of 10,000 m. The stratigraphic section is complete and fossil is abundant. It is China. One of the ideal areas for studying the continental Cretaceous strata. The Songliao Basin is a north-eastern, north-north-eastward, rhomboid basin surrounded by hills and mountains. The western part is the Daxinganling Mountains, the east is Zhangguangcai Ridge, the north is the Xiaoxing'anling Mountains, and the south is the Kangping-Faku hilly area. Inside the basin is a plain swamp formed by the alluvial waters of the Songhua River, Nenjiang River and Liaohe River. The ground elevation is 120~300m, the length is 750km, the width is 330-370km, and the area is about 260,000km2 (including 118,000km2 in Heilongjiang). It is one of the largest typical continental sedimentary basins in the world.