ORDOS DESERT

Wade-Giles romanization Mao-wu-su Sha-mo, Pinyin Maowusu Shamo, desert on a plateau in the southern section of the Inner Mongolian autonomous ch' (region), China. The Ordos fills the area inside the great northern bend of the Huang Ho (Yellow River) and is bounded by the provincial boundaries with Shensi province and with the Hui Autonomous Region of Ningsia, a frontier that follows closely the line of the Great Wall of China. Structurally, the Ordos Desert is the northern part of the great raised basin-platform that occupies northern Shensi, where its peneplained surface (i.e., worn down by erosion to a nearly flat plain) is masked by massive deposits of loess (wind-blown silt). This basin consists of immense thicknesses of largely undisturbed sedimentary rocks of the Carboniferous and Jurassic periods. These include rich coal strata, particularly along the eastern border of the basin, and the whole basin plateau has potential as an oil-producing area. Generally, the surface features of the Ordos comprise undulating hills and plains. There are some higher ridges; the Arhiso Mountains in the northwest, which overlook the Huang Ho, represent the raised western edge of the basin structure, while in the southeast the ridge of the Pai-y Mountains constitutes the northern limit of the drainage basin of the Wei River. The general elevation of the plateau is about 3,600 feet (1,100 m), and the ridges rarely rise above 6,500 feet (2,000 m). Much of the area, particularly the lower-lying depressions, is covered with shifting sands; blown by the strong prevailing northwesterly winds of winter, they are constantly encroaching on the territory of northern Shensi bordering the desert. There are very few streams in the Ordos region. The climate is extremely arid, the country receiving less than 10 inches (250 mm) of rain annually. The only sizable river is the Tu-ssu-t'u River, flowing west into the upper Huang Ho. In the south of the Ordos are great numbers of salt pools and lakes with no drainage outlet; many of these have dried up, leaving deposits of salt and soda. Vegetation is extremely sparse, particularly in the drier northern and western sections. In the lake basins there are salt meadows with sedge swamps along the seasonal watercourses. The vegetation gradually improves in the wetter east and south, where much of the surface, apart from the shifting sand dunes, is covered with drought-resistant grasses and sparse shrubs. The whole area is very sparsely populated, human life being generally supported only by nomadic herds of sheep, goats, and horses. The population is almost entirely Mongol. To prevent the spread of the sand dunes, the Chinese government in the 1960s planted a wide belt of drought-resistant trees along the southern and eastern edges of the desert. In the 1970s and '80s, Chinese scientists unearthed more than 20 human fossils from 30,000 to 60,000 years old at Hsiao-ch'iao-pan in the Sjara-osso River valley. The terms Ordos man and Ordosian culture are applied to their findings.