What are the basic features of China landform outline?

China's topography is high in the west and low in the east, with a ladder-like distribution, which is divided into three steps from west to east, which has become a remarkable feature of the overall outline of China landform.

(1) The Qinghai-Tibet Plateau, with an average elevation of 4,000-5,000 meters, is the first topographic step in China. A series of tall mountains surround the plateau, with the Himalayas, the highest mountain in the world, in the south, with an average elevation of over 6,000 meters. Seven peaks are over 8,000 meters, making it the highest Mount Everest in the world. Kunlun Mountain, Altun Mountain and Qilian Mountain are distributed in the north, and Minshan Mountain and Hengduan Mountain are arranged in the east. The terrain is connected with the secondary terrain ladder with huge drop.

There are a series of mountains on the plateau that strike nearly east-west or northwest-southeast, all of which are above 5,000-6,000 meters above sea level, mainly including Mount Hoh Xil, bayan har, Mount Tanggula, Mount Gangdise and Mount Nyainqentanglha. Between these mountains, there are plateaus and basins with gentle surface undulations and vast areas, as well as dotted lakes. The edge of the plateau is the birthplace of famous rivers in Asia, such as the Yangtze River and the Yellow River. The top of the mountain is covered with snow, the plateau is covered with green grass, and the lakes and mountains complement each other.

(2) To the north and east of the outer edge of the Qinghai-Tibet Plateau, the terrain is obviously reduced, and the eastern part is bounded by Daxing 'anling, Taihang Mountain, Wushan Mountain and Xuefeng Mountain, which constitutes a second-class terrain ladder in China, mainly consisting of vast plateaus and basins, with a series of tall mountains distributed in between. Adjacent to the northwest of the Qinghai-Tibet Plateau is the largest Tarim Basin in China, with an altitude of about 1000 meters. Further north is Junggar basin; About 500 meters above sea level; East and West Tianshan Mountains stand between great basin, with an altitude of 4,000-5,000 meters, and some peaks are as high as 6,000 meters. There are also many fault basins in the mountains. On the northeast side of the plateau, Hexi Corridor and Alashan Plateau are connected with the northern foot of Qilian Mountain, with an altitude of 1000- 1500m. Because these basins and plateaus live inland, there is drought and little rain, and Gobi and desert are widely distributed in the basin; Along rivers and canals, oasis agriculture, intermittent distribution, hilltops, crystal snow. On the second terrain step east of the eastern edge of the Qinghai-Tibet Plateau, Inner Mongolia Plateau, Ordos Plateau, Loess Plateau and Yunnan-Guizhou Plateau are distributed from north to south, with an altitude of1000-2000m. Due to the difference of surface composition and internal and external forces, the surface morphology is very different, including some undulating terrain, overgrown grassland, some deserts and numerous sand dunes. Some ravines are vertical and horizontal, and beams and headlands are everywhere; Some dams are numerous and karst landforms are widely distributed. There are many mountains on the plateau, such as Yinshan Mountain, Liupanshan Mountain, Luliang Mountain, Qinling Mountain, Daba Mountain, Dalou Mountain, Wuling Mountain and Miaoling Mountain. Most of them are between1500-2500m above sea level, and a few peaks reach over 3000m. The elevation of Sichuan Basin is relatively low, mostly below 500 meters.

(3) On the edge of the second-level terrain ladder, the east of the line from Daxinganling to Xuefeng Mountain is a third-level terrain ladder, which is dominated by plains, hills and low mountains. Northeast Plain, North China Plain and the middle and lower reaches of the Yangtze River are distributed from north to south, mostly below 200 meters above sea level. It is the most important agricultural base in China, and also an economic zone with dense population, towns and villages, strong industrial base and convenient transportation. In the south of the Yangtze River, there are low mountains and hills. The vast area is less than 500 meters above sea level and the ground is uneven. Flat valley plains and basins are interlaced with low mountains and hills. To the east of these plains and low mountains, there is also a series of mountains in the northeast direction-Changbai Mountain, Qian Shan and Luzhong Mountain, as well as Xianxialing, Wuyishan and Daiyun Mountain along the coast of Zhejiang and Fujian, with altitudes mostly between 500- 1500m. Although the absolute height is not large, it is quite towering from the plains and valleys at low altitude. To the east of the coastline is a wide continental shelf shallow sea, which is a part of the gentle extension of the mainland to the ocean, with a water depth of100-200m. 400-600 kilometers wide, it is an important fishing ground and rich in oil resources. On the continental shelf, there are many islands, among which Taiwan Province Island and Hainan Island are the most famous.

The topography is high in the west and low in the east, which is the most remarkable feature of the overall landform profile of China, and has the most remarkable influence on rivers. Most of the famous rivers in China originate from the first and second steps, which flow from west to east, connecting the east-west traffic and strengthening the connection between the coast and the inland. The terrain in this area is steep, the river is cut, the slope is large, the flow velocity is fast, the canyons are row upon row, and the hydraulic resources are rich, which is suitable for the cascade development of large-scale water control projects.