Terrain Evolution of China Seas and Land Since the Indo‐China Movement and Characteristics of the Stepped Landform

Terrain is the situation of the ground rising and falling, which is controlled by both the endogenetic and exogenic forces of the earth. The terrain reflects the internal structure, construction, and evolution of the curst. Free-air gravity anomalies are related to topography and geomorphology. It is considered that the curst that under mountains is thicker than that under plains by the equalization principle. There is a mirror image relationship between crust thickness and terrain relief. The map series of geology and geophysics of China seas and land include figures of tectonic framework and evolution of tectonic framework. The temporal evolution of the main blocks is studied in both of the maps, which elaborate the evolution of China's terrain as a “Seesaw”. This paper analyzes the geomorphological features by the free-air gravity anomaly map and Moho depth distribution map. In accordance with the principle of tectonic landform classification, the general characteristics of China seas and land is viewed as a whole which shows five terrain steps from west to east on the basis of three geomorphological ladders of Chinese land.