China's topography was completely formed around the emergence of
the Qinghai-Tibet Plateau, the most important geological event over
the past several million years. Taking a bird's-eye view of China,
the terrain gradually descends from west to east like a staircase.
Due to the collision of the Indian and Eurasian plates, the young
Qinghai-Tibet Plateau rose continuously to become the top of the
four-step "staircase," averaging more than 4,000 m above sea level,
and called "the roof of the world." Soaring 8,848 m above sea level
on the plateau is Mt. Qomolangma, the world's highest peak and the
main peak of the Himalayas. The second step includes the gently
sloping Inner Mongolia Plateau, the Loess Plateau, the
Yunnan-Guizhou Plateau, the Tarim Basin, the Junggar Basin and the
Sichuan Basin, with an average elevation of between 1,000 m and
2,000 m. The third step, dropping to 500-1,000 m in elevation,
begins at a line drawn around the Greater Hinggan, Taihang, Wushan
and Xuefeng mountain ranges and extends eastward to the coast of
the Pacific Ocean. Here, from north to south, are the Northeast
Plain, the North China Plain and the Middle-Lower Yangtze Plain.
Interspersed amongst the plains are hills and foothills. To the
east, the land extends out into the ocean, in a continental shelf,
the fourth step of the staircase. The water here is less than 200 m
deep. The area of mountains and hills and plateaus account for 65
percent of the total land area of China.