1. WHERE/WHAT IS GOBI DESERT?
Unlike the romanticized image of deserts with sweeping sand dunes, most of the landscape of The Gobi consists of rocky, hard-packed terrain. While the solid land underfoot made it easier to transverse the desert, catapulting the Gobi onto the scene of history as a viable trade route, there was a very little settled human occupation in the area until modern times. A clue to the historical perception of the Gobi as an inhospitable region is found in its name, which derives from the Mongolian word for "very large and dry."
The Gobi is a rain shadow desert formed by the Himalaya range, which prevents rain-carrying clouds from reaching it. It is roughly crescent-shaped, lying between the Altai and Khangai mountain ranges in the north and the Pei Mountains in the south. The eastern side of the desert is fringed by the Sinkiang region, a large basin that extends towards the Plateau of Tibet. Towards the west of the Gobi lies the Greater Khingan Range.
The Gobi occupies a vast arc of land 1,000 miles (1,600 km) long and 300 to 600 miles (500 to 1,000 km) wide, with an estimated area of 500,000 square miles (1,300,000 square km).
Physiography - The Gobi consists of the Gaxun, Junggar, and Trans-Altai Gobi in the west, the Eastern, or Mongolian, the Gobi in the center and east, and the Alxa Plateau in the south.
The Trans-Altai Gobi is situated between the eastern spurs of the Mongolian Altai and Gobi Altai mountains to the north and east, respectively, and the Bei Mountains to the south. The plain is elevated, sharp, and rugged. Alongside the plains and the isolated group of low, rounded hills is a fairly extensive mountain area that extends more than six miles (10km) out into the plain. The mountains are barren and broken up by dry ravines.
The Eastern Gobi is similar to the western regions, with elevations varying from 2,300 to 5,000 feet (700 to 1,500 meters), but it receives somewhat more precipitation—up to 8 inches (200 mm) per year—though it lacks significant rivers. The underground aquifers have relatively abundant quantities of water and are only partly mineralized. They are also near the surface, feeding small lakes and springs. The vegetation, however, is sparse, consisting mainly of herb wormwood in coarse, grayish-brown soil. In the moister depressions, there are the usual salt marshes and grassy swamps. In the northern and eastern outlying regions, where more precipitation occurs, the landscape of the desert gradually becomes less harsh, or sometimes even steppe-like.
Climate - The climate is acutely continental and dry: winter is severe, spring is dry and cold, and summer is warm. The annual temperature range is considerable, with average lows in January reaching −40 °F (−40 °C) and average highs in July climbing to 113 °F (45 °C); daily temperature ranges also can be quite large. The annual total precipitation varies from less than 2 inches (50 mm) in the west to more than 8 inches (200 mm) in the northeast. Monsoon like conditions exists in the eastern regions, which receive most of their precipitation in summer. Northerly and northwesterly winds prevail over the Gobi in autumn, winter, and spring.
Gobi Soil - The drainage of the desert is largely underground; surface rivers have little constant flow. Mountain streams are confined to the Gobi’s fringes and even then quickly dry up as they disappear into the loose soil or the salty, enclosed depressions. Many rivers flow only in summer. On the other hand, subterranean water is widespread and of sufficient quality to allow cattle raising.
During the Holocene Epoch (i.e., about the past 11,700 years), the Gobi’s lakes have shrunk in size, leaving a series of terraces considerably farther from and higher than the present shorelines. Indeed, Lakes Orog and Bööntsagaan, in the easternmost Mongolian Altai, and Lake Ulaan, in the northwestern Gobi Altai, are but shadows of their former selves.
The soil of the Gobi is chiefly grayish brown and brown carbonaceous, gypseous, coarse gravel, often combined with sandy salt marshes and takyr.
Sands of the Gobi Deserts
Despite the fact that much of the Gobi desert consists of gravel or rocky terrain, the few sand dunes that do exist continue to draw scientific inquiry and tourists alike. There are two major theories about the origins of the sand dunes in Mongolia. One theory, which is the more popular theory among scientists, states that the sands were carried into the desert on wind currents, much the way that water can carry sand. This theory has gained popularity as science has been able to track wind currents in the region, and the sand dunes have been proven to have developed along traditional wind paths. While this is the more predominant theory, an alternative idea exists that claims the sand dunes were originally a product of water erosion.