The Tibet Autonomous Region forms the major part of the Qinghai-Tibet Plateau, the world’s highest plateau of incomparable grandeur and scenery. Varied landforms contribute to the region’s complex natural environment and abundant natural resources on the Tibetan Plateau. Generally speaking, Tibet has a terrain descending northwest to southeast, with the average elevation decreasing from over 5,000 meters to 4,000 meters.
Tibet’s topography roughly features the Himalayan mountain area, southern Tibet valley, Northern Tibet Plateau and eastern Tibet Canyon.
Himalayan mountain area: Situated in south Tibet, it is composed of several mountain ranges running from east to west, with an average elevation of 6,000 meters. Mount Qomolangma on the China-Nepal border stands at 8,848.13 meters above sea level, being the highest peak in the world. The Himalayas are crowned with snow all year round. Climate and topography on the northern and southern sides of the mountains vary greatly.
Southern Tibet valley: Lying between the Kangdese and Himalayan mountains, the valley is drained by the Yarlung Zangbo River and its tributaries. The area abunds in river valley flat lands and lake basin flat lands of varying width. With fertile soil, it is the major farming area in Tibet.
Northern Tibet Plateau: Lying among the Kunlunshan, Tanggula, Kangdese and Nyainqentanglha mountains, the plateau covers two-thirds of the region’s total area. Many round hills with gentle slops mingle with a number of basins, making the area the major region of animal husbandry in Tibet.
Eastern Tibet Canyon: It is the well-known Hengduanshan Mountain Range. Located east of Nagqu, the canyon is formed by some high mountains extending east-west before turning south-north, with the three rivers—Nujiang, Lancangjiang and Jinshajiang—running in between. The snow-capped peaks, thick forests halfway up the mountains and green fields at the foot constitute a gorgeous scenery peculiar to the canyon.
Some 20 million years ago, the collision of the Eurasian and Indian plates gave birth to the world’s youngest highland—the Qinghai-Tibet Plateau. Mountains created as a result form the skeleton of the plateau. They basically extend either from east to west or from south to north.
Mountains Running From East to West
Kunlunshan Mountains: Kunlunshan runs west-east on the northern fringe of the Tibetan Plateau, with an average elevation of 5,500-6,000 meters. To its north are the Tarim Basin in Xinjiang and the Qaidam Basin in Qinghai; to its south are low-lying land, lake basins and wide valleys, extending to join the Northern Tibet Plateau. Muztag, rising 6,973 meters above sea level, is the highest peak in the area.
Karakorum-Tanggula Mountains: The major part of the Karakorum Mountains lies on the border between Xinjiang and Kashmir. Running eastward, it forms the Tanggula Mountains at 90°E, marking the border between Tibet and Qinghai.
Kangdese-Nyainqentanglha Mountains: Lying at the southern edge of the Northern Tibet Plateau, the mountains serve as the border between north and south and southeast Tibet, and the demarcation line for rivers that flow within and out of the region. Kangrinboqe, with an elevation of 6,656 meters, is the main peak of the Kangdese Mountains; and Nyainqentanglha, rising 7,162 meters above sea level, is the highest peak of the Nyainqentanglha Mountains.
Himalayan Mountains: Zigzagging through the southern part of the Tibetan Plateau, the Himalayas comprise many parallel mountains running from east to west. The major part of the Himalayas lies on the border between China and India, and between China and Nepal. Extending some 2,400 km, it is 200-300 km wide and has an average elevation of over 6,000 meters. In this part of the world there are 50-plus peaks each with an elevation of over 7,000 meters, and over 10 with an elevation over 8,000 meters. Qomolangma, rising 8,848.13 meters above sea level, towers over surrounding peaks in the middle part of the Himalayas on the Sino-Nepalese border. Within an area of 5,000-plus square km surrounding the world’s highest are four more peaks each with an elevation of over 8,000 meters and 42 rising over 7,000 meters.
Mountains Running From South to North
Hengduanshan Mountains: Hengduanshan is a combination of several parallel mountains with deep river valleys between them. These mountains from west to east include Bexoi La, Taniantaweng and Markam mountains. Having an average elevation of 4,000-5,000 meters, they are extensions of the Nyainqentanglha Mountains and Tanggula Mountains.
The huge mountains on the Qinghai-Tibet Plateau have bred modern glaciers. Melted ice become the source of such well known rivers in Asia as the Yangtze River, Yarlung Zangbo, Nujiang, Lancangjiang and Indus. Tibet is one of the regions in China which have the largest number of rivers. According to incomplete statistics, the region has 20-plus rivers each with a drainage area of over 10,000 square km.
Some of the rivers in Tibet flow into the sea while the others are just inland waters. The most important rivers are the Yarlung Zangbo, Jinshajiang, Lancangjiang, Pum Qu, Langqen Zangbo and Sengge Zangbo. The average annual runoff stands at 448.2 billion cubic meters.
Most of the rivers that ultimately empty into the Pacific Ocean or the Indian Ocean are distributed in the border areas of east, south and west Tibet. They include the Jinshajiang River (the upper reaches of the Yangtze River), Lancangjiang River (called Mekong outside China), and Nujiang River (called Salween outside China) in the east; the Yarlung Zangbo (called Brahmaputra outside China) in the south; and Langqen Zangbo (Xiangquan River) and Sengge Zangbo (also called Shiquan River, the upper reaches of the Indus) in the west.
The inland rivers are mainly distributed on the Northern Tibetan Plateau. Snows on high mountains are headwaters of these rivers, which are usually short and developed surrounding an endorheic lake. Most of them are seasonal waters. Their lower reaches either disappear in the wildness or accumulated into a lake at lower land.
Yarlung Zangbo River
Yarlung Zangbo, seen as “Mother River” by Tibetans, is the largest river in the Tibet Autonomous Region. Originating in the Gyima Yangzong Glacier (5,500 meters above sea level) in Zhongba County at the northern foot of the Himalayas, it runs 2,057 km in China (ranking fifth in China in terms of length), draining an area of 240,000 square km (sixth in China). With the drainage area having an average elevation of 4,500 meters, the Yarlung Zangbo is the highest river in the world.
About 1 million people, or 37 percent of Tibet’s total population, live in the area drained by the Yarlung Zangbo River, where cultivated land amounts to over 150,000 hectares, or 41.67 percent of the region's total. The area is also home to some major cities and towns, including Lhasa, Xigaze, Gyangze, Zetang and Bayi.
The Yarlung Zangbo River cleaves a straight niche from west to east before reaching the juncture of Mainling and Medog counties, where it swerves around towering Namjagbarwa (7,782 meters), the highest peak in the eastern section of the Himalayas, creating the largest, U-shaped canyon in the world. In 1994, some Chinese scientists made an expedition trip along the canyon. Data published by the State Bureau of Surveying and Mapping following the expedition shows that the canyon starts from the Daduka Village, Mainling County in the north and ends at Parcoka Village, Medog in the south. Stretching 504.6 km, the canyon is 2,268 meters deep on average, with the deepest point being 6,009 meters. The Colorado Canyon in the United States is 440 km in length while the Colca Canyon in Peru is 3,203 meters deep. In September 1998, the State Council officially approved the name of the canyon as "Yarlung Zangbo Daxiagu" (Yarlung Zangbo Grand Canyon).
Tibet boasts the largest number of lakes in China. There are more than 1,000 lakes in the region, which cover a total area of 23,800 square km, about 30 percent of the nation's total lake area. Nam Co, Serling Co and Zhari Nam Co have an area of over 1,000 square km each. Forty-seven lakes cover more than 100 square km each and 612 others cover more than 1 square km each.
The lakes in Tibet can also be divided into two categories: exorheic and endorheic lakes. The endorheic lakes are mainly the products of orogenic movement and stratigraphic fracture. The exorheic lakes include barrier lakes formed after mud-rock flow and landslide blocked the river course and glacial lake formed as a result of glacier action.
The largest lake in Tibet, it is situated between Damxung County of Lhasa, the capital city of the Tibet Autonomous Region, and Bangoin County of Nagqu Prefecture. "Nam Co" means a heaven lake or a sacred lake in Tibetan. It is a holy place in Tibetan Buddhism.
Lying 4,718 meters above sea level, Nam Co stretches 70-plus km from east to west and 30-plus km from north to south, covering a total area of 1,900 square km. It is the second largest and the highest saltwater lake in China. It is more than 33 meters deep at the deepest point. Melting snow from the Nyainqentanglha Mountain and some surrounding streams of varying sizes provide it with water sources. The sky blue water is clear and transparent.
In addition to Nam Co, Tibet is also home to many other well-known sacred lakes. They include Mapam Yumco, Yamzhog Yumco and Lamuna Co.