Gobi - geography.

Gobi - geography. Gobi, extensive desert area of southern Mongolia and northern China. The largest desert in Asia, it is also known as Shamo, the Chinese word for "sand desert." The Gobi, which is about 1,600 km (about 1,000 mi) in extent from east to west and about 1,000 km (about 600 mi) from north to south, has a total area of 1,300,000 sq km (500,000 sq mi). It is bounded by the Da Hinggan Ling (Greater Khingan Range) on the east, the Altun Shan and Nan Shan mountains on the south, the Tian Shan mountains on the west, and the Altay and Hangayn Nuruu (Khangai) mountains and Yablonovyy Range on the north. The Gobi is formed by a series of small basins within a larger basin rimmed by upland. The elevations of these basins range from 900 m (3,000 ft) above sea level in the east to 1,500 m (5,000 ft) in the west. The basins are divided by low, flat-topped ranges and isolated hills that are the result of faulting action. The floors of the basins are unusually flat and level, and are formed of a desert pavement of small gravel resting on granite or metamorphic rock. There are, however, large areas of sedimentary rocks and some lava bed areas. Much of the sand and fine material has been blown away, but tall sand dunes rise along the desert's southern edge. The Gobi receives only a little snow in winter and no more than 200 to 250 mm (8 to 10 in) of rain along the northern and eastern edges, mainly in summer. Only the southeastern portion of the Gobi is completely waterless. Temperatures range from -40°C (-40°F) in winter to 32°C (90°F) in summer. The remainder of the region, approximately three-quarters of the area, has a thin growth of grass, scrub, and thorn sufficient to feed the flocks of the nomadic herders who live there; water is available in wells and occasional shallow lakes. The borders of the Gobi to the north and northwest are fertile, and grassy steppes or prairies lie at the southeastern edge of the desert area. In recent years, overgrazing and overplowing in the desert's borders have resulted in erosion and loss of plant cover that have caused the Gobi to spread, especially in northern China. This growing desertification has worsened dust and sand storms, which can blanket parts of East Asia and have serious environmental and economic effects. Chinese authorities began working to reverse the loss of vegetation in the early 21st century. The desert is crossed from north to south by traditional trade routes and, alongside of them, a railroad from Ulaanbaatar, Mongolia (extending north to the main Trans-Siberian Railroad), to Jining on China's main east-west line in the north. Archaeological finds in the Gobi include remains of Eolithic, Upper Paleolithic, Neolithic, and Bronze Age civilizations. The first Europeans to traverse the Gobi were Venetian traveler Marco Polo and his father and uncle, who crossed the region about 1275. The next recorded crossing is that of the French Jesuit priest Jean François Gerbillon in the 1680s. In modern times a number of expeditions have explored the Gobi, including expeditions commanded by the Swedish explorer Sven Anders Hedin. In the 1920s the American Museum of Natural History sponsored a series of expeditions in the Gobi under the leadership of the American naturalist Roy Chapman Andrews. The expeditions discovered fossilized dinosaur eggs belonging to the previously unknown Oviraptor species. Microsoft ® Encarta ® 2009. © 1993-2008 Microsoft Corporation. All rights reserved.