1. The terrain is high in the west and low in the east, with a stepped distribution. China's topography is high in the west and low in the east, and it descends step by step from west to east, forming a step-by-step slope that gradually decreases, which has become a remarkable feature of the general outline of China landform. The Qinghai-Tibet Plateau is the highest first-class terrain ladder in China, with an average elevation of 4,000-5,000 meters. 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. 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 composed of vast plateaus and basins, in which a series of tall mountains are distributed. 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. Inner Mongolia Plateau, Ordos Plateau, Loess Plateau and Yunnan-Guizhou Plateau are distributed from north to south on the second terrain step east of the eastern edge of the Qinghai-Tibet Plateau, 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 the headlands are all over; 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. East of the line from Daxing 'anling to Xuefeng Mountain on the edge of the second-level terrain ladder is a third-level terrain ladder, which is mainly composed of 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. There are many mountains with obvious ups and downs. China is a mountainous country, with mountains accounting for 1/3 of the country's total area. From the Pamirs in the westernmost part to the eastern coastal areas, from the Heilongjiang coast in the northernmost part to the South China Sea coast, large and small mountains crisscross, forming the skeleton of China landform and controlling the spatial distribution pattern of landform. If the divided plateaus, rugged mountain plateaus, hilly plateaus and Fangshan hilly basin in the basin are included, and the gently undulating hills are added, the mountains in a broad sense account for about 65% of the total land area. Although the mountains in China are criss-crossed, they are widely distributed, but their distribution has certain regularity, which is not only the skeleton of the macro-landform distribution pattern, but also an important geographical dividing line. The mountains in China can be divided into the following types according to their strike: ① The north-south mountains are located in the middle of China, and from north to south there are mainly Helan Mountain, Liupanshan Mountain and the famous Hengduan Mountain. The Hengduan Mountains in western Sichuan and northern Yunnan are composed of a series of parallel high mountains and deep valleys, mainly Qionglai Mountain, Daxue Mountain, Shaluli Mountain, Quiet Mountain, Nu Mountain and Gaoligong Mountain, most of which are above 4000 meters above sea level. There are Dadu River, Yalong River, Jinsha River, Lancang River and Nujiang River between the mountains, and the valleys are deep, forming a parallel landscape with obvious height difference. This north-south mountain range divides the whole country into east and west parts. Most of the mountains in the west are mountains above 3500 meters above sea level and extremely high mountains above 5000 meters, such as Himalayas, Gangdise Mountain, Kunlun Mountain, Qilian Mountain and Tianshan Mountain. The mountains mainly run northwest and northwest. The eastern part is mostly Zhongshan and low mountains below 3500 meters above sea level, mainly from north to east, such as Daxinganling, Taihang Mountain, Xuefeng Mountain, Changbai Mountain and Wuyishan. Only the main peak of Yushan Mountain in Taiwan Province Province and Taibai Mountain in Qinling Mountains are above 3,500 meters above sea level. ② There are three east-west mountain ranges: the northernmost one is Tianshan Mountain and Yinshan Mountain, which are roughly distributed between 40 and 43 north latitude. Tianshan Mountain runs through the middle of Xinjiang, with a length of 1500 km and a width of 250-300 km from north to south. The central column is roughly located between 33 and 35 north latitude, with Kunlun Mountain in the west, Qinling Mountain in the middle and Huaiyang Mountain in the east. The southernmost column is Nanling, which is roughly located between 25 and 26 north latitude. The distance between these three east-west mountains is roughly equal, about 8 latitudes apart, which is obviously equidistant. Kunlun Mountain and Tianshan Mountain in the west are more than 4000-5000 meters above sea level, which become the natural dividing line between Qinghai-Tibet Plateau, Tarim Basin and Junggar Basin. The elevation of Yinshan Mountain and Qinling Mountain in the east is about 1 1,000-2,000m, while the elevation of Nanling Mountain is only 1 1,000m, which also reflects the general trend of high in the west and low in the east. Due to the low terrain in the east of China, these mountains still look tall and straight, and they are all important geographical dividing lines in China. For example, Yinshan Mountain constitutes the edge of the Inner Mongolia Plateau, and Qinling Mountain is the watershed of the Yellow River, the Yangtze River and the Huaihe River, and it is also an important physical and geographical dividing line that distinguishes the north and the south of China. Although the mountain is broken and messy, and the altitude is not high, Nanling is not only the watershed between the Yangtze River and the Pearl River, but also the dividing line between Central China and South China, which is also of great significance in physical geography. ③ The NW-trending mountains are mainly distributed in the western half of China, mainly including Altai Mountain, Qilian Mountain, Karakorum Mountain, Kekexili Mountain, Tanggula Mountain, Gangdise Mountain and Nyainqentanglha Mountain. The Himalayas on the south side of the Qinghai-Tibet Plateau, in the western section, also runs northwest, and gradually turns from east to west, projecting southward in an arc-shaped mountain range. Most of these mountains are steep and cold, and modern glaciers are widely developed. ④NE-trending mountains are mainly distributed in the east, and are divided into west column, east column and outer column from west to east. The west column includes Daxing 'anling, Taihang Mountain, Wushan Mountain, Wuling Mountain and Xuefeng Mountain. Dongzhu starts from Changbai Mountain in the north, passes through Qianshan Mountain and low hills in Shandong to Wuyishan Mountain, and is distributed in Taiwan Province Island outside the mainland. There are 62 peaks, accounting for 2/3 of the total island area, and the main peak, Yushan, is 3997 meters above sea level, which is not only the highest peak in Taiwan Province Province, but also the highest peak in East China. The above-mentioned numerous mountains crisscross and divide China into many grids, and plateaus, basins, plains and basins are embedded in these grids, forming a grid-like distribution pattern of China landforms. The landform fluctuates obviously, and the height difference between regions is also a feature of China landform. The Qinghai-Tibet Plateau has an average elevation of 4,500 meters, but the Sichuan Basin on its east side is about 500 meters above sea level. To the south of Kunlun Mountain is the northern Tibetan Plateau with an altitude of 5000 meters, but the Tarim Basin in the north is 1000 meters above sea level. It is rare to have such a huge height difference across a mountain. As far as the whole country is concerned, Mount Everest is 8848 meters above sea level, while Aiding Lake in Turpan Basin of Xinjiang is 155 meters above sea level, with a height difference of 9903 meters, which is the highest in the world. The huge height difference in some areas is even more spectacular: the Namgyabawa peak at the eastern end of the Himalayas is as high as 7756 meters above sea level, but the Medog area in the Yarlung Zangbo River basin is only 700 meters above sea level, and the horizontal distance between the two places is about 40 kilometers, and the relative altitude is actually more than 7000 meters; Gongga Mountain in western Sichuan is 7556 meters above sea level, but the adjacent Dadu River Valley is 1600 meters above sea level, with a height difference of 5997 meters. Even in Taiwan Province Province in the east of China, there is a huge height difference between Yushan Mountain, which is 3997 meters above sea level, and Tainan Plain nearby, which is below 100 meters above sea level. The undulating surface forms different types of mountain vertical landscapes in various places, which makes the natural geographical environment of China more complicated. 3. The landform types are complex and diverse. China is a vast country with complicated geological structure, surface composition and climatic and hydrological conditions. According to the landform, it can be divided into five basic types: mountain, plateau, hill, basin and plain. Mountains and plateaus have the widest areas, accounting for 33% and 26% of the national area respectively; Followed by the basin, accounting for19%; The proportion of hills and plains is small, which are 10% and 12% respectively. There are four plateaus, four great basin and three plains embedded in criss-crossing mountainous areas, forming a grid-like framework in China. Qinghai-Tibet Plateau, Inner Mongolia Plateau, Loess Plateau and Yunnan-Guizhou Plateau are the four major plateaus in China. The Qinghai-Tibet Plateau is located between the Himalayan Mountains in the south and the Kunlun Mountains, Altun Mountains and Qilian Mountains in the north, and it is in a large grid west of Minshan-Qionglai Mountain-Jinping Mountain. It is the largest plateau with the highest altitude in China. The Inner Mongolia Plateau, the Loess Plateau and the Yunnan-Guizhou Plateau are all distributed on the second-step terrain, separated by Yinshan Mountain, Qinling Mountain, Dalou Mountain and Northwest Guangxi Mountain, and distributed from north to south in turn. Due to the difference of ground composition and external factors, the plateau landform is significantly different and has different shapes. Inner Mongolia Plateau is located in the northern inland, with dry climate, little rain, weak running water, open surface and gentle topography. It is a plateau with obvious form and relatively complete surface preservation in China Plateau. The Loess Plateau lies between the southern Inner Mongolia Plateau and the Qinling Mountains. In the dry and cold climate of Quaternary Glacier, loess deposition flourished, forming the world-famous Loess Plateau. As the climate changed to warm and humid during the interglacial period, loose loess was strongly eroded by flowing water, which made ravines criss-cross and ridges everywhere in most parts of the plateau. Limestone is widely distributed in Yunnan-Guizhou Plateau, and the climate is warm and humid. Except for the flat plateau surface in central Yunnan, eastern Yunnan and northwestern Guizhou, most areas are divided into uneven surface by tributaries such as Yangtze River, Pearl River and Yuanjiang River. In the limestone distribution area, karst landforms are fully developed. Tarim Basin, Junggar Basin, Qaidam Basin and Sichuan Basin are the four great basin of China, and they all belong to structural fault depression areas. The Qaidam Basin, with the highest altitude of 2600-3000m, is surrounded by Kunlun Mountain, Altun Mountain and Qilian Mountain. Structurally, it belongs to the Qaidam Depression of the East Kunlun Fold System, covering an area of more than 200,000 square kilometers, and is the third great basin in China. The climate of the basin is dry, and there are many salt lakes and marshes, and there are many kinds of salt resources and abundant reserves. Non-ferrous metals, ferrous metals, rare metal resources and petroleum resources are also abundant. The basin has long sunshine time, rich light energy resources and high agricultural output; The area along the river is rich in pasture and animal husbandry plays an important role, so it is called "cornucopia". With an area of 530,000 square kilometers, Tarim Basin is the largest basin in China. Because it goes deep into the hinterland, surrounded by mountains, the terrain is closed and the climate is extremely dry. Vegetation is sparse, dry erosion, wind erosion and accumulated wind are obvious, and the largest Taklimakan desert in China is distributed. From the edge of the basin to the inside of the basin, the surface components and landforms are arranged in a ring shape. Around the edge of the basin, there are fertile oases with developed agriculture and concentrated population, which are nourished by melted snow on both sides of the mountain. Since ancient times, it has been an important channel to contact the "Silk Road". Junggar basin is located between Tianshan Mountain and Altai Mountain, covering an area of 380,000 square kilometers. It is the second great basin in China, and the Gurbantunggut Desert, the second largest desert in China, is located in the basin. The western part of the basin is a semi-closed basin with low mountains and many gaps, with a little more precipitation and dense vegetation, mainly fixed and semi-fixed sand dunes. The grassland is vast and the animal husbandry is developed. The southern edge of the basin is watered by the melting water of Tianshan snow and ice, with developed oasis agriculture and concentrated towns. Sichuan Basin is located in the east of Qinghai-Tibet Plateau and the west of Wushan, between Dalou Mountain and Daba Mountain in the north and south, surrounded by mountains, and the basin is complete in shape. Because the Mesozoic purple sand and shale are widely distributed, it is also called "red basin" or "purple basin". The drainage area is about165,000 square kilometers. Although it is the smallest of the four great basin, it is located in the subtropical zone, with warm and humid climate, dense water system, large population, fertile soil, rich products and developed economy. It is one of the richest areas in China and has the reputation of "Land of Abundance". Northeast Plain, North China Plain and the middle and lower reaches of the Yangtze River are the three major plains in China, which are concentrated in the grid between the east-west direction and the northeast mountain on the third-level terrain ladder in the east. They are the main agricultural bases in China with vast area, low terrain, convenient transportation and dense population. The Northeast Plain is located in the northern part of Yanshan Mountains, between Daxing 'anling, Xiaoxing 'anling and Changbai Mountain. It is about 1000 km long from north to south and 400 km wide from east to west, covering an area of 350,000 square kilometers. It is the largest plain in China, characterized by a large area of black soil and a wide distribution of swamps. North China Plain is the second largest plain in China, with Dabie Mountain and Yanshan Mountain in the north and south, Taihang Mountain and Funiu Mountain in the west, Shandong Hill and Yellow Sea and Bohai Sea in the east, covering an area of 365,438+100000 square kilometers. Because it is mainly formed by alluvial sediments of the Yellow River, Huaihe River and Haihe River, it is also called Huanghuaihai Plain. The terrain is low and flat, and the ground slope is very small. In many areas, the riverbed is higher than the plains on both sides of the river, and the above-ground rivers and inter-river depressions are alternately distributed, which constitutes the unique characteristics of the North China Plain. The middle and lower reaches of the Yangtze River plain is located along the middle and lower reaches of the Yangtze River east of Wushan, mainly including the two lakes plain, Poyang Lake plain, Jiangsu-Anhui plain along the Yangtze River and the Yangtze River Delta. It is beaded from east to west, covering an area of about 200,000 square kilometers, and is the third largest plain in China. Characterized by low-lying, densely covered lakes, densely covered rivers and canals, and contiguous paddy fields, China is a famous land of plenty. The hills in China are also mainly distributed in the east, that is, on the third terrace, with the largest concentration in the vast areas east of Xuefeng Mountain and south of the Yangtze River, which are collectively called "Southeast Hills". Among them, the south of the Yangtze River and the north of Nanling are called Jiangnan hills; South of Nanling, Guangdong and Guangxi are called the hills of Guangdong and Guangxi; To the east of Wuyishan, Zhejiang and Fujian provinces are called Zhejiang and Fujian hills. The hills north of the Yangtze River are distributed in a small range, mainly in Shandong hills and Liaodong hills. The southeast hills are mainly distributed on both sides of a series of northeast-trending middle and low mountains, among which there are randomly arranged large and small red rock basins, and the surface morphology is mainly characterized by hills with low absolute height and relatively small ups and downs. Due to different lithology, thick red sandstone and conglomerate are distributed in the hilly area south of the Yangtze River. Granite and rhyolite are widely distributed in hilly areas of Zhejiang and Fujian. In the west of Guangdong and Guangxi hills, limestone is widely distributed and karst landforms are developed. Shandong hills and Liaodong hills are located in Shandong Peninsula and Liaodong Peninsula, and are composed of metamorphic rocks and huagangyan. The ground is relatively broken, the coast is tortuous, and there are many harbors and islands. It is a famous fruit producing area in warm temperate zone. In addition to the above five basic landform types, there are many special landforms, such as glaciers, periglacial, sandstorms, loess, karst, volcanoes and coasts. This is caused by the vertical fluctuation of the terrain and the obvious difference between the land and sea. The western part of China is towering into the sky, and there are many extremely high mountains above the snow line. Modern glaciers are widely distributed, starting from Altai Mountain in the north, reaching Himalayas and Yulong Mountain in the north of Yunnan in the south, reaching the peaks between Xuebaoding in Songpan and western Sichuan in the east and Pamirs in the west, with a total area of 58,523 square kilometers, making China the most developed country with modern glaciers in the middle and low latitudes in the world. Modern glaciers are divided into hanging glaciers, barrel glaciers, valley glaciers and flat-topped glaciers, of which valley glaciers are the most common and the largest. According to the physical properties, Nyainqentanglha Mountain can be roughly divided into marine glaciers and continental glaciers. Ice lakes, caves, caves, ice towers, ice walls and other ice crystal landscapes often appear on glaciers. The ebb and flow of glaciers also forms ice erosion and moraine landforms such as ice bucket, ice mound, ridge, suspended valley, U-shaped valley, terminal moraine, lateral moraine, bottom moraine and moraine terrace. Glacier landforms such as stone rivers, stone seas, debris flows, deposits and mud tongues formed by freezing weathering, snowmelt water and gravity are also very common. China is one of the countries in the world with vast desert Gobi area. China's desert Gobi is mainly distributed in the north, including the arid and semi-arid areas in the northwest and Inner Mongolia, with a total area of 654.38 0.28 million square kilometers, accounting for about 654.38 0.3% of the national area. To the west of Wushaoling in Helan Mountain, the desert area is the largest and most concentrated. Taklimakan Desert, Gurbantunggut Desert, Badain Jaran Desert and Tengger Desert are the four major deserts in China, all of which are distributed in this area. On the edge and periphery of the great desert, there are belt-shaped or ring-shaped Gobi distribution. On the southern edge of the desert, it starts from Kunlun Mountain in the west, Changbai Mountain in the east, the Great Wall in the north, and Qinling and Huaiyang Mountain in the south. A large area of loess and loess-like sediments are distributed in east-west belts, with a total area of about 600,000 square kilometers, with the most concentrated in central and eastern Gansu, northwestern Shaanxi and Shanxi, forming the largest loess plateau in the world, with an area of about 390,000 square kilometers. Weathered materials in the desert are the direct source of loess. In areas where loess is concentrated, the thickness of loess cover is about100-200m, forming a unique loess source, beam and headland landform. Due to the loose texture of loess, poor anti-corrosion ability and serious soil erosion, the ground is often divided by gullies, which makes it particularly broken and the river sediment concentration is extremely high. Carbonate rocks are widely distributed in China, covering an area of about 6.5438+0.3 million square kilometers, accounting for about 654.38+0/7 of the total area of the country, especially in Guangxi, Guizhou and eastern Yunnan, where rock formations are developed and the distribution area of carbonate rocks accounts for more than 50% of the total area of these areas. Because thick and pure limestone is widely distributed, it rises to a higher position through tectonic movement, and many faults, cracks and joints appear. Under the conditions of low latitude and hot and humid climate, rainwater, surface water and groundwater are continuously dissolved along limestone cracks, forming a karst landform with beautiful water in Shan Qi. Picturesque peak forests, deep and tortuous caves, hidden rivers and natural bridges can be seen everywhere. Karst landforms are widely distributed and have many types, which are beyond the reach of other countries in the world. It is a perfect natural museum of karst landforms and a famous tourist attraction with the best landscape in the world. Since Cretaceous, the climate in Jiangnan is warm and hot, and a set of continental red rock series has accumulated in low-lying basins. Hard thick conglomerate and glutenite are eroded by running water along faults and joints, forming Danxia terrain with many cliffs and peaks; Sand shale with relatively soft lithology forms hills with relatively low terrain, thus forming a unique red bed landform in Jiangnan area. There are more than 600 volcanoes in China, and volcanic cones are generally small and distributed in groups. Lava platforms formed by lava flows are often distributed near volcanic cones, forming volcanic landforms. Volcanoes in China are mainly distributed at the intersection of east-northeast and east-west structural belts, except in the west and the middle of Kunlun Mountain. There are more than 270 volcanic rocks on the north and south sides of the eastern section of Yinshan Mountain. They are distributed on the basalt lava platform, with a relative height of tens of meters or more than 100 meters, which is the largest volcanic group in China. There are more than 100 volcanic rocks in Changbai Mountain Volcano Group, which are widely distributed on Changbai Mountain basalt lava platform 1400 square kilometers. It is the second largest volcanic group in China. Bai Yunfeng, the first peak in Northeast China, is an active volcano, which erupted three times at 1597, 1668 and 1702. Tianchi on the top of the mountain is the former crater. In addition, there are volcanic landforms such as volcanic hills or basalt lava platforms in Taiwan Province Province, the northern part of Hainan Island and Leizhou Peninsula, the north and south banks of the Yangtze River near Nanjing in the lower reaches of the Yangtze River and Tengchong near the western edge of the southern section of Hengduan Mountains in western Yunnan. There are many islands scattered in the southeast of China, with mainland coastline 18000 km and island coastline 14000 km. Coastlines are divided into three categories: plain coast (sandy coast), mountain coast (rocky coast) and biological coast. In addition, there are bedrock islands, alluvial islands and coral islands, which make coastal landforms and islands complex and diverse.