The smallest basin in China is

The smallest of the four great basin in China is the Qaidam Basin.

Qaidam basin is one of the three inland basins in China, and it is a closed giant intermountain fault basin. Located in the northwest of Qinghai Province and the northeast of Qinghai-Tibet Plateau, mainly in Haixi Mongolian and Tibetan Autonomous Prefecture. Northwest and north reach Altun Mountain; Southwest to Kunlun Mountain; There is Qilian Mountain in the northeast, covering an area of 257,768 square kilometers. Inland is rich in iron ore, copper ore, tin ore, salt ore and other minerals, so it is called "cornucopia". Qaidam is a Mongolian language, which was compiled by the Qing rulers to clear the language barrier and consolidate the rule of the northwest frontier after pacifying the western regions, and was personally examined and approved by Emperor Qianlong. It is clearly recorded in Sixteen Volumes, an important reference book for studying the history and geography of northwest ethnic minorities: "Mongolian, Qaidam, is vast." Riverside, spacious, hence the name. " Deliberately means "vast", but due to some subjective and objective reasons such as history, some people also use the meaning of "salt"? This explanation, in fact, is also controversial in academic circles.

Qaidam basin is a plateau basin, located in the northwest of Qinghai Province, mainly in Haixi Mongolian and Tibetan Autonomous Prefecture. It is a closed basin surrounded by Kunlun Mountain, Altun Mountain, Qilian Mountain and other mountains, with a range of 9016 ′ e-9916 ′ e, 35 00 ′ n-39 20 ′ n. The basin is slightly triangular, with an area of about 800 kilometers from east to west and 300 kilometers from north to south. It is one of the three inland basins in China.

Qaidam Basin is the highest elevation basin among the four great basin in China. Qaidam is not only a salt world (there are many salt lakes and swamps in the southeast), but also rich in oil, coal and various metal deposits, such as oil in Lenghu, coal in You Xiang and lead-zinc mine in Xitieshan. Therefore, the Qaidam Basin has the reputation of "cornucopia".

Qaidam basin belongs to plateau continental climate. Characterized by drought. The annual precipitation decreases from 200mm in the southeast to 15mm in the northwest, and the annual average relative humidity is 30-40%, and the lowest can be lower than 5%. The annual average temperature in the basin is below 5℃, and the temperature changes dramatically. The annual absolute temperature difference can reach above 60℃, the daily temperature difference is often around 30℃, and it can drop below 0℃ at night in summer. The wind is strong, and the number of gale days above magnitude 8 can reach 25-75 days, and there can even be a gale of 40 meters per second in the west, with strong wind erosion.

The natural landscape of Qaidam Basin is arid desert, and the main soil types are salinized desert soil and gypsum desert soil. The latter is mainly distributed in the west of the basin, and meadow soil and swamp soil are generally salinized. ? Vegetation is sparse, with a single species, less than 200 species in total, mainly shrubs, semi-shrubs and herbs with high drought resistance, and more halophytes. The vegetation structure is simple, and about 6/ 10 associations are composed of one or several species.

In the foothill alluvial fan and alluvial plain, the desert vegetation community is mainly composed of ramie, ephedra, Haloxylon ammodendron and red sand shrubs; In salt marshes, along salt lakes and rivers, Cyperaceae plants densely form grass mounds, among which the dominant halophytes are Juncus purpurea, Seriphidium sericeum and black moss. Reed and Leymus chinensis dominate the periphery of salt lakes and swamps.

The fauna in Qaidam Basin is characterized by the transition from Meng Xin to Qinghai-Tibet. Wild animals mainly include wild camels, wild donkeys, wild yaks, antelopes, green sheep, marmots, wolves, Ma Xiong, roe deer, foxes and badgers. Due to reclamation and hunting, wild animals have been greatly reduced, and some are on the verge of extinction.