Indian Ocean

From Wikipedia, the free encyclopedia

The Indian Ocean, not including the Antarctic region.

The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface.^[1] It is bounded by Asia—including India, after which the ocean is named^[2][3][4][5]—on the north, on the west by Africa, on the east by Australia, and on the south by the Southern Ocean (or, depending on definition, by Antarctica).^[6]

As one component of the World Ocean, the Indian Ocean is delineated from the Atlantic Ocean by the 20° east meridian running south from Cape Agulhas, and from the Pacific Ocean by the meridian of 146°55' east.^[7] The northernmost extent of the Indian Ocean is approximately 30° north in the Persian Gulf. The ocean is nearly 10,000 km (6200 mi) wide at the southern tips of Africa and Australia, and its area is 73,556,000 km² (28,350,000 mi²),^[8] including the Red Sea and the Persian Gulf.

The Indian Ocean's volume is estimated to be 292,131,000 km³ (70,086,000 mi³).^[9] Small islands dot the continental rims. Island nations within the ocean are Madagascar (the world's fourth largest island), Bahrain, Comoros, Maldives, Mauritius, Seychelles and Sri Lanka. The archipelago of Indonesia and the island nation of Timor-Leste border the ocean on the east.

Geography

Bathymetric map of the Indian Ocean

The African, Indian, and Antarctic crustal plates converge in the Indian Ocean at the Rodrigues Triple Point. Their junctures are marked by branches of the mid-oceanic ridge forming an inverted Y, with the stem running south from the edge of the continental shelf near Mumbai, India. The eastern, western, and southern basins thus formed are subdivided into smaller basins by ridges.

The ocean's continental shelves are narrow, averaging 200 kilometres (125 mi) in width. An exception is found off Australia's western coast, where the shelf width exceeds 1,000 kilometres (600 mi). The average depth of the ocean is 3,890 m (12,762 ft). Its deepest point is Diamantina Deep in Diamantina Trench, at 8,047 m (26,401 ft) deep; also sometimes considered is Sunda Trench, at a depth of 7,258–7,725 m (23,812–25,344 ft).^[10] North of 50° south latitude, 86% of the main basin is covered by pelagic sediments, of which more than half is globigerina ooze. The remaining 14% is layered with terrigenous sediments. Glacial outwash dominates the extreme southern latitudes.

The major choke points include Bab el Mandeb, Strait of Hormuz, the Lombok Strait, the Strait of Malacca and the Palk Strait. Seas include the Gulf of Aden, Andaman Sea, Arabian Sea, Bay of Bengal, Great Australian Bight, Laccadive Sea, Gulf of Mannar, Mozambique Channel, Gulf of Oman, Persian Gulf, Red Sea and other tributary water bodies. The Indian Ocean is artificially connected to the Mediterranean Sea through the Suez Canal, which is accessible via the Red Sea.

Climate

The climate north of the equator is affected by a monsoon climate. Strong north-east winds blow from October until April; from May until October south and west winds prevail. In the Arabian Sea the violent Monsoon brings rain to the Indian subcontinent. In the southern hemisphere, the winds are generally milder, but summer storms near Mauritius can be severe. When the monsoon winds change, cyclones sometimes strike the shores of the Arabian Sea and the Bay of Bengal. The Indian Ocean is the warmest ocean in the world.

Hydrology

Among the few large rivers flowing into the Indian Ocean are the Zambezi, Shatt al-Arab, Indus, Narmada, Ganges, Brahmaputra, Jubba and Irrawaddy River. The ocean's currents are mainly controlled by the monsoon. Two large circular currents, one in the northern hemisphere flowing clockwise and one south of the equator moving anticlockwise, constitute the dominant flow pattern. During the winter monsoon, however, currents in the north are reversed.

Deep water circulation is controlled primarily by inflows from the Atlantic Ocean, the Red Sea, and Antarctic currents. North of 20° south latitude the minimum surface temperature is 22 °C (72 °F), exceeding 28 °C (82 °F) to the east. Southward of 40° south latitude, temperatures drop quickly.

Surface water salinity ranges from 32 to 37 parts per 1000, the highest occurring in the Arabian Sea and in a belt between southern Africa and south-western Australia. Pack ice and icebergs are found throughout the year south of about 65° south latitude. The average northern limit of icebergs is 45° south latitude.

Subsurface features

As the youngest of the major oceans ^[11] it has active spreading ridges that are part of the worldwide system of mid-ocean ridges:-

• Carlsberg Ridge
• Southwest Indian Ridge
• Southeast Indian Ridge
• Central Indian Ridge

The Ninety East Ridge runs north-south at meridian 90°E, dissecting the Indian Ocean into eastern and western halves.

The Chagos-Laccadive Ridge is another submerged mountain range runs approximately north-south between Lakshadweep, the Atolls of the Maldives and the Chagos Archipelago.

The Kerguelen Plateau is a small, submerged continent of volcanic origin in the southern Indian Ocean.

The Mascarene Plateau is 2000 km long undersea plateau that lies east of Madagascar.

Trade

A dhow off the coast of Kenya

The Indian Ocean provides major sea routes connecting the Middle East, Africa, and East Asia with Europe and the Americas. It carries a particularly heavy traffic of petroleum and petroleum products from the oil fields of the Persian Gulf and Indonesia. Large reserves of hydrocarbons are being tapped in the offshore areas of Saudi Arabia, Iran, India, and Western Australia. An estimated 40% of the world's offshore oil production comes from the Indian Ocean.^[12] Beach sands rich in heavy minerals, and offshore placer deposits are actively exploited by bordering countries, particularly India, Pakistan, South Africa, Indonesia, Sri Lanka, and Thailand.

Marine life

The warmth of the Indian Ocean keeps phytoplankton production low, except along the northern fringe and in a few scattered spots elsewhere; life in the ocean is thus limited. Fishing is confined to subsistence levels, because its fish are of great and growing importance to the bordering countries for domestic consumption and export. Fishing fleets from Russia, Japan, South Korea, and Taiwan also exploit the Indian Ocean, mainly for shrimp and tuna.

Endangered marine species include the dugong, seals, turtles, and whales.

Plastic pollution threatens the eastern coast of Mozambique Channel.

History

The economically important Silk Road (red) and spice trade routes (blue) were blocked by the Ottoman Empire in ca. 1453 with the fall of the Byzantine Empire. This spurred exploration, and a new sea route around Africa was found, triggering the Age of Discovery.

The world's earliest civilizations in Mesopotamia (beginning with Sumer), ancient Egypt, and the Indian subcontinent (beginning with the Indus Valley civilization), which began along the valleys of the Tigris-Euphrates, Nile and Indus rivers respectively, all developed around the Indian Ocean. Civilizations soon arose in Persia (beginning with Elam) and later in Southeast Asia (beginning with Funan).

During Egypt's first dynasty (c. 3000 BC), sailors were sent out onto its waters, journeying to Punt, thought to be part of present-day Somalia. Returning ships brought gold and myrrh. The earliest known maritime trade between Mesopotamia and the Indus Valley (c. 2500 BC) was conducted along the Indian Ocean. Phoenicians of the late 3rd millennium BC may have entered the area, but no settlements resulted.

The Indian Ocean's relatively calmer waters opened the areas bordering it to trade earlier than the Atlantic or Pacific oceans. The powerful monsoons also meant ships could easily sail west early in the season, then wait a few months and return eastwards. This allowed Indonesian peoples to cross the Indian Ocean to settle in Madagascar.

In the 2nd or 1st century BC, Eudoxus of Cyzicus was the first Greek to cross the Indian Ocean. Hippalus is said to have discovered the direct route from Arabia to India around this time. During the 1st and 2nd centuries AD intensive trade relations developed between Roman Egypt and the Tamil kingdoms of the Cheras, Cholas and Pandyas in Southern India. Like the Indonesian peoples above, the western sailors used the monsoon to cross the ocean. The unknown author of the Periplus of the Erythraean Sea describes this route, as well as the commodities that were traded along various commercial ports on the coasts of the Horn of Africa and India circa 1 AD. Among these trading settlements were Mosylon and Opone on the Red Sea littoral.

From 1405 to 1433, Admiral Zheng He led large fleets of the Ming Dynasty on several treasure voyages through the Indian Ocean, ultimately reaching the coastal countries of East Africa.^[13]

British heavy cruisers Dorsetshire and Cornwall under Japanese air attack and heavily damaged on April 5, 1942

In 1497, Portuguese navigator Vasco da Gama rounded the Cape of Good Hope and became the first European to sail to India and later the Far East. The European ships, armed with heavy cannon, quickly dominated trade. Portugal attempted to achieve pre-eminence by setting up forts at the important straits and ports. They dominated trade and discovery along the coasts of Africa, and Asia until the mid 17th century. Later the Portuguese were challenged by other European powers. The Dutch East India Company (1602–1798) sought control of trade with the East across the Indian Ocean. France and Britain established trade companies for the area. Spain established a major trading operation in the Philippines and the Pacific. By 1815, Britain became the principal power in the Indian Ocean.

The opening of the Suez Canal in 1869 revived European interest in the East, but no nation was successful in establishing trade dominance. Since World War II the United Kingdom was forced to withdraw from the area, to be replaced by India, the USSR, and the United States. The last two tried to establish hegemony^{[citation needed]} by negotiating for naval base sites. Developing countries bordering the ocean, however, seek to have it made a "zone of peace"^{[citation needed]} so that they may use its shipping lanes freely. The United Kingdom and United States maintain a military base on Diego Garcia atoll in the middle of the Indian Ocean.

On 26 December 2004, the countries surrounding the Indian Ocean were hit by a tsunami caused by the 2004 Indian Ocean earthquake. The waves resulted in more than 226,000 deaths and over 1 million people were left homeless.

In the late 2000s, the ocean evolved into a hub of pirate activity. By 2013, attacks off the Horn region's coast had steadily declined due to active private security and international navy patrols.^[14]

Culture and literature

The Indian Ocean is known as Ratnakara in the ancient Sanskrit literature. Ratnakara means "the mine of gems". It is also called Hind Mahasagar in Hindi and other Indian languages.

Bordering countries and territories

Heading roughly clockwise, the states and territories (in italics) with a coastline on the Indian Ocean (including the Red Sea and Persian Gulf) are:

Africa

 South Africa,  Mozambique,  Madagascar,  French Southern and Antarctic Lands,  France (Réunion, Mayotte),  Mauritius,  Comoros,  Tanzania,  Seychelles,  Kenya,  Somalia,  Djibouti,  Eritrea,  Sudan,  Egypt

Asia

 Egypt (Sinai Peninsula),  Israel,  Jordan,  Saudi Arabia,  Yemen,  Oman,  United Arab Emirates,  Qatar,  Bahrain,  Kuwait,  Iraq,  Iran,  Pakistan,  India,  Maldives,  British Indian Ocean Territory,  Sri Lanka,  Bangladesh,  Burma,  Thailand,  Malaysia,  Singapore  Indonesia,  Cocos (Keeling) Islands,

Australasia

Ashmore and Cartier Islands,  Indonesia,  Timor-Leste,  Australia

Southern Indian Ocean

Heard Island and McDonald Islands,  French Southern and Antarctic Lands

Major ports and harbours

The Port of Singapore is the busiest port in the Indian Ocean, located in the Strait of Malacca where it meets the Pacific. Mumbai Port is the chief trading port in India on the coast of the Indian Ocean, often known as "The Gateway of India". Chennai Port is the second largest port in India and the busiest on the east coast. Mormugao Port, Panambur, Kochi, Kolkata, Port Blair, Visakhapatnam, Paradip, Ennore, Tuticorin and Nagapattinam are the other major ports in India. South Asian ports include Chittagong in Bangladesh, Colombo, Hambantota and Galle in Sri Lanka, and Karachi in Pakistan. Aden is a major port in Yemen and controls ships entering the Red Sea. Major African ports on the shores of the Indian Ocean include: Mombasa (Kenya), Dar es Salaam, Zanzibar (Tanzania), Durban, East London, Richard's Bay (South Africa), Beira (Mozambique), and Port Louis (Mauritius). Zanzibar is especially famous for its spice export. Other major ports in the Indian Ocean include Muscat (Oman), Yangon (Burma), Jakarta, Medan (Indonesia), Fremantle (port servicing Perth, Australia) and Dubai (UAE).
Chinese companies are making investments in several Indian Ocean ports, including Gwadar, Hambantota, Colombo and Sonadia. This has sparked a debate about the strategic implications of these investments.^[15]

Marginal seas

Marginal seas, gulfs, bays and straits of the Indian Ocean include:

1. Arabian Sea
2. Persian Gulf
3. Red Sea
4. Gulf of Oman
5. Gulf of Aden
6. Strait of Bab-el-Mandeb connecting Arabian Sea
7. Gulf of Kutch
8. Gulf of Khambat
9. Palk Strait connecting Arabian Sea and Bay of Bengal
10. Bay of Bengal
11. Andaman Sea
12. Malacca Strait
13. Mozambique Channel
14. Great Australian Bight
15. Gulf of Mannar
16. Laccadive Sea

Gobi Desert

From Wikipedia, the free encyclopedia

Gobi Desert (Говь)
Desert
Gobi Desert landscape in Ömnögovi Province, Mongolia
Countries	Mongolia, China
Mongolian Aimags	Bayankhongor, Dornogovi, Dundgovi, Govi-Altai, Govisümber, Ömnögovi, Sükhbaatar
Chinese Autonomous Region	Inner Mongolia
Landmark	Nemegt Basin
Length	1,500 km (932 mi), SE/NW
Width	800 km (497 mi), N/S
Area	1,295,000 km2 (500,002 sq mi)
The Gobi Desert lies in the territory of the People's Republic of China and Mongolia.

The Gobi (/ˈɡoʊ.bi/; Mongolian: Говь, Govi, "semidesert"; Chinese: 戈壁; pinyin: Gēbì ) is a large desert region in Asia. It covers parts of northern and northwestern China, and of southern Mongolia. The desert basins of the Gobi are bounded by the Altai Mountains and the grasslands and steppes of Mongolia on the north, by the Taklamakan Desert to the West, by the Hexi Corridor and Tibetan Plateau to the southwest, and by the North China Plain to the southeast. The Gobi is most notable in history as part of the great Mongol Empire, and as the location of several important cities along the Silk Road.

The Gobi is made up of several distinct ecological and geographic regions based on variations in climate and topography. One is the Eastern Gobi desert steppe ecoregion, a palearctic ecoregion in the deserts and xeric shrublands biome, home to the Bactrian camel and various other animals.^[1] It is a rain shadow desert formed by the Himalaya range blocking rain-carrying clouds from the Indian Ocean from reaching the Gobi territory.

Geography

The Gobi measures over 1,600 km (1,000 mi) from southwest to northeast and 800 km (500 mi) from north to south. The desert is widest in the west, along the line joining the Lake Bosten and the Lop Nor (87°-89° east). It occupies an arc of land 1,295,000 km² (500,000 sq mi)^[2] in area as of 2007; it is the fifth-largest desert in the world and Asia's largest. Much of the Gobi is not sandy but has exposed bare rock.

The Gobi has several different Chinese names, including 沙漠 (Shāmò, a generic term for deserts) and 瀚海 (Hànhǎi, "endless sea"). In its broadest definition, the Gobi includes the long stretch of desert and semi-desert area extending from the foot of the Pamirs, 77° east, to the Greater Khingan Mountains, 116°-118° east, on the border of Manchuria; and from the foothills of the Altay, Sayan, and Yablonoi mountain ranges on the north to the Kunlun, Altyn-Tagh, and Qilian mountain ranges, which form the northern edges of the Tibetan Plateau, on the south.^{[citation needed]}

Gobi desert near Dunhuang

A relatively large area on the east side of the Greater Khingan range, between the upper waters of the Songhua (Sungari) and the upper waters of the Liao-ho, is reckoned to belong to the Gobi by conventional usage. Some geographers and ecologists prefer to regard the western area of the Gobi region (as defined above): the basin of the Tarim in Xinjiang and the desert basin of Lop Nor and Hami (Kumul), as forming a separate and independent desert, called the Taklamakan Desert.

Archeologists and paleontologists have done excavations in the Nemegt Basin in the northwestern part of the Gobi Desert (in Mongolia), which is noted for its fossil treasures, including early mammals, dinosaur eggs, and prehistoric stone implements, some 100,000 years old.^{[citation needed]}

Climate

Gobi by NASA World Wind

Sand dunes in Inner Mongolia Autonomous Region, China

A summer monsoon produces a flash flood, 2005

Bactrian camels by the sand dunes of Khongoryn Els, Gurvansaikhan NP, Mongolia.

The sand dunes of Khongoryn Els, Gurvansaikhan NP, Mongolia

The Gobi is a cold desert, with frost and occasionally snow occurring on its dunes. Besides being quite far north, it is also located on a plateau roughly 910–1,520 metres (2,990–4,990 ft) above sea level, which contributes to its low temperatures. An average of approximately 194 millimetres (7.6 in) of rain falls annually in the Gobi. Additional moisture reaches parts of the Gobi in winter as snow is blown by the wind from the Siberian Steppes. These winds cause the Gobi to reach extremes of temperature ranging from –40°C (–40°F) in winter to +50°C (122°F) in summer.^[3]

The climate of the Gobi is one of great extremes, combined with rapid changes of temperature of as much as 35 °C (63 °F). These can occur not only seasonally but within 24 hours.

Temperature

	Sivantse (1190 m)	Ulaanbaatar (1150 m)
Annual mean	−2.5 °C (27.5 °F)	2.8 °C (37.0 °F)
January mean	−26.5 °C (−15.7 °F)	−16.5 °C (2.3 °F)
July mean	17.5 °C (63.5 °F)	19.0 °C (66.2 °F)
Extremes	−43 to 38 °C (−45 to 100 °F)	−47 to 38.6 °C (−53 to 101 °F)

In southern Mongolia, the temperature has been recorded as low as −32.8 °C (−27.0 °F). In contrast, in Alxa, Inner Mongolia, it rises as high as 37 °C (99 °F) in July.

Average winter minimums are a frigid −40 °C (−40 °F) while summertime temperatures are warm to hot, with highs that range up to 50 °C (122 °F). Most of the precipitation falls during the summer.

Although the southeast monsoons reach the southeast parts of the Gobi, the area throughout this region is generally characterized by extreme dryness, especially during the winter, when the Siberian anticyclone is at its strongest. Hence, the icy sandstorms and snowstorms of spring and early summer plus early January (winter)

Conservation, ecology, and economy

The Gobi Desert is the source of many important fossil finds, including the first dinosaur eggs.

Despite the harsh conditions, these deserts and the surrounding regions sustain many animals, including black-tailed gazelles, marbled polecats, bactrian camels, Mongolian wild ass and sandplovers. They are occasionally visited by snow leopards, brown bears, and wolves. Drought-adapted shrubs in the desert included gray sparrow's saltwort, gray sagebrush, and low grasses such as needle grass and bridlegrass. Several large nature reserves have been established in the Gobi, including Gobi Gurvansaikhan National Park, Great Gobi A and Great Gobi B Strictly Protected Area.

The area is vulnerable to trampling by livestock and off-road vehicles (effects from human intervention are greater in the eastern Gobi Desert, where rainfall is heavier and may sustain livestock). In Mongolia, grasslands have been degraded by goats, which are raised by nomadic herders as source of cashmere wool. The economic trends of livestock privatization and the collapse of the urban economy have caused people to return to subsistence rural lifestyles, away from urbanization.

Large copper and gold deposits located at Oyuu Tolgoi, about 80 kilometers from the Chinese border into Mongolia, are being investigated for development as mining operations.^[4] The Oyu Tolgoi copper and gold mine, under construction by Rio Tinto in the South Gobi Desert, is expected to begin operation in early 2013, and is the biggest economic undertaking in the country's history. Rio Tinto estimates that taxes, royalties and dividends generated by the Oyu Tolgoi project is expected to add a third to the country's gross domestic product by 2020. Rio Tinto forecasts average annual production of 450,000 tonnes of copper and 330,000 ounces of gold, and with 1.4 billion tonnes of reserves and a resource of 3.1 billion tonnes, the mine is expected to last for more than 50 years. ^[5]

The mine has been and remains controversial. There is significant opposition in Mongolia's parliament to the terms under which the mine will proceed, and some are calling for the terms to be renegotiated. Specifically, the contention revolves primarily around the question of whether negotiations were fair (Rio Tinto is far better resourced) and whether Rio Tinto will pay adequate taxes on the revenues it derives from the mine (an agreement was reached whereby the operation will be exempt from windfall tax. ^[6]

Desertification

Currently, the Gobi desert is expanding at an alarming rate, in a process known as desertification. The expansion is particularly rapid on the southern edge into China, which has seen 3,600 km² (1,390 sq mi) of grassland overtaken every year by the Gobi Desert. Dust storms, which used to occur regularly in China, have increased in frequency in the past 20 years, mainly due to desertification. They have caused further damage to China's agriculture economy.

The expansion of the Gobi is attributed mostly to human activities, notably deforestation, overgrazing, and depletion of water resources. China has tried various plans to slow the expansion of the desert, which have met with some small degree of success, but no major effects. The most recent plan involves the planting of the Green Wall of China, a huge ring of newly planted forests; the government hopes the forests will help stabilize the soil, retain moisture, and act as a buffer against further desertification.

Ecoregions of the Gobi

The Gobi, broadly defined, can be divided into five distinct dry ecoregions.

• Eastern Gobi desert steppe, the easternmost of the Gobi ecoregions, covering an area of 281,800 km² (108,804 sq mi). It extends from the Inner Mongolian Plateau in China northward into Mongolia. It includes the Yin Mountains and many low-lying areas with salt pans and small ponds. It is bounded by the Mongolian-Manchurian grassland to the north, the Yellow River Plain to the southeast, and the Alashan Plateau semi-desert to the southeast and east.

• Alashan Plateau semi-desert, lies west and southwest of the Eastern Gobi desert steppe. It consists of the desert basins and low mountains lying between the Gobi Altai range on the north, the Helan Mountains to the southeast, and the Qilian Mountains and northeastern portion of the Tibetan Plateau on the southwest.

• Gobi Lakes Valley desert steppe, ecoregion lies north of Alashan Plateau semi-desert, between the Gobi Altai range to the south and the Khangai Mountains to the north.

• Dzungarian Basin semi-desert, includes the desert basin lying between the Altai mountains on the north and the Tian Shan range on the south. It includes the northern portion of China's Xinjiang province and extends into the southeastern corner of Mongolia. The Alashan Plateau semi-desert lies to the east, and the Emin Valley steppe to the west, on the China-Kazakhstan border.

• Tian Shan range, separates the Dzungarian Basin semi-desert from the Taklamakan Desert, which is a low, sandy desert basin surrounded by the high mountain ranges of the Tibetan Plateau to the south and the Pamirs to the west. The Taklamakan Desert ecoregion includes the Desert of Lop.

Eastern Gobi desert steppe

A Khulan (Mongolian Wild Ass) on a hill in the eastern Gobi of Mongolia at sunset.

The surface is extremely diversified, although there are no great differences in vertical elevation. Between Ulaanbaatar (48°00′N 107°00′E) and the small lake of Iren-dubasu-nor (43°45′N 111°50′E), the surface is greatly eroded. Broad flat depressions and basins are separated by groups of flat-topped mountains of relatively low elevation 150 to 180 m (490 to 590 ft)), through which archaic rocks crop out as crags and isolated rugged masses. The floors of the depressions lie mostly between 900 to 1,000 m (3,000 to 3,300 ft) above sea-level. Farther south, between Iren-dutiasu-nor and the Hwang-ho, comes a region of broad tablelands alternating with flat plains, the latter ranging at altitudes of 1000–1100 m and the former at 1,070 to 1,200 m (3,510 to 3,940 ft). The slopes of the plateaus are more or less steep, and are sometimes penetrated by "bays" of the lowlands.

As the border-range of the Hyangan is approached, the country steadily rises up to 1,370 m (4,490 ft) and then to 1,630 m (5,350 ft). Here small lakes frequently fill the depressions, though the water in them is generally salt or brackish. Both here and for 320 km (199 mi) south of Ulaanbaatar, streams are frequent and grass grows more or less abundantly. Through all the central parts, until the bordering mountains are reached, trees and shrubs are utterly absent. Clay and sand are the predominant formations; the watercourses, especially in the north, being frequently excavated 2 to 3 m (6 ft 7 in to 9 ft 10 in) deep. In many places in the flat, dry valleys or depressions farther south, beds of loess, 5 to 6 m (16 to 20 ft) thick, are exposed. West of the route from Ulaanbaatar to Kalgan, the country presents approximately the same general features, except that the mountains are not so irregularly scattered in groups but have more strongly defined strikes, mostly east to west, west-north-west to east-south-east, and west-south-west to east-north-east.

The altitudes are higher, those of the lowlands ranging from 1,000 to 1,700 m (3,300 to 5,600 ft), and those of the ranges from 200 to 500 m (660 to 1,640 ft) higher, though in a few cases they reach altitudes of 2,400 m (7,900 ft). The elevations do not form continuous chains, but make up a congeries of short ridges and groups rising from a common base and intersected by a labyrinth of ravines, gullies, glens and basins. But the tablelands, built up of the horizontal red deposits of the Han-gai (Obruchev's Gobi formation) which are characteristic of the southern parts of eastern Mongolia, are absent here or occur only in one locality, near the Shara-muren river. They are greatly intersected by gullies or dry watercourses. Water is scarce, with no streams, no lakes, no wells, and precipitation falls seldom. The prevailing winds blow from the west and northwest, and the pall of dust overhangs the country as in the Takla Makan and the desert of Lop. Characteristic of the flora are wild garlic, Kalidium gracile, wormwood, saxaul, Nitraria schoberi, Caragana, Ephedra, saltwort and the grass Lasiagrostis splendens. The taana wild onion Allium polyrrhizum is the main browse eaten by many herd animals, and Mongolians claim that this is essential to produce the correct, slightly hazelnut-like flavour of camel airag (fermented milk).

This great desert country of Gobi is crossed by several trade routes, some of which have been in use for thousands of years. Among the most important are those from Kalgan (at the Great Wall) to Ulaanbaatar (960 km (597 mi)); from Jiuquan (in Gansu) to Hami 670 km (416 mi); from Hami to Beijing (2,000 km (1,243 mi)); from Hohhot to Hami and Barkul; and from Lanzhou (in Gansu) to Hami.

Alashan Plateau semi-desert

The southwestern portion of the Gobi, known also as the Hsi-tau and the Little Gobi, fills the space between the great north loop of the Yellow River on the east, the Ejin River on the west, and the Qilian Mountains and narrow rocky chain of Longshou, 3,200 to 3,500 m (10,500 to 11,500 ft) in altitude, on the southwest. The Ordos Desert, which covers the northeastern portion of the Ordos Plateau, in the great north loop of the Huang He, is part of this ecoregion. It belongs to the middle basin of the three great depressions into which Potanin divides the Gobi as a whole.

"Topographically," says Nikolai Przhevalsky, "it is a perfectly level plain, which in all probability once formed the bed of a huge lake or inland sea." He concludes this based on the level area of the region as a whole, the hard saldgine clay and the sand-strewn surface and, lastly, the salt lakes which occupy its lowest parts. For hundreds of kilometers, nothing can be seen but bare sands; in some places they continue so far without a break that the Mongols call them Tengger (i.e. sky). These vast expanses are absolutely waterless, nor do any oases relieve the unbroken stretches of yellow sand, which alternate with equally vast areas of saline clay or, nearer the foot of the mountains, with barren shingle. Although on the whole a level country with a general altitude of 1,000 to 1,500 m (3,300 to 4,900 ft), this section, like most other parts of the Gobi, is crowned by a chequered network of hills and broken ranges going up 300 m higher. The vegetation is confined to a few varieties of bushes and a dozen kinds of grasses and herbs, the most conspicuous being saxaul (Haloxylon ammondendron) and Agriophyllum gobicum. The others include prickly convolvulus, field wormwood (Artemisia campestris), acacia, Inula ammophila, Sophora flavescens, Convolvulus ammanii, Peganum and Astragalus, but all dwarfed, deformed and starved. The fauna consists of little but antelope, wolf, fox, hare, hedgehog, marten, numerous lizards and a few birds, e.g. the sandgrouse, lark, stonechat, sparrow, crane, Henderson's Ground Jay (Podoces hendersoni), Horned Lark (Eremophila alpestris), and Crested Lark (Galerida cristata).

Dzungarian Basin semi-desert

The structure here is that of the mighty T'ien Shan, or Heavenly Mountains, running from west to east. It divides the northern one-third of Sinkiang from the southern two-thirds. On the northern side, rivers formed from the snow and glaciers of the high mountains break through barren foothill ranges and flow out into an immense, hollow plain. Here the rivers begin to straggle and fan out, and form great marshes with dense reed-beds. Westerners call this terrain the Dzungarian desert. The Chinese also call it a desert, but the Mongols call it a 'gobi'—that is, a land of thin herbage, more suitable for camels than for cows, but capable also, if herds are kept small and moved frequently, of sustaining horses, sheep, and goats. The herbage comprises a high proportion of woody, fragrant plants. Gobi mutton is the most aromatic in the world.^[7]

The Yulduz valley or valley of the Haidag-gol (43°N 83°E–43°N 86°E) is a mini desert enclosed by two prominent members of the Shanashen Trahen Osh mountain range, namely the chucis and the kracenard pine rallies, running perpendicular and far from one another. As they proceed south, they transcend and transpose, sweeping back on east and west respectively, with Lake Bosten in between. These two ranges mark the northern and the southern edges respectively of a great swelling, which extends eastward for nearly twenty degrees of longitude. On its northern side, the Chol-tagh descends steeply, and its foot is fringed by a string of deep depressions, ranging from Lukchun (130 m (427 ft) below sea level) to Hami (850 m (2,789 ft) above sea-level). To the south of the Kuruk-tagh lie the desert of Lop Nur, the Kum-tagh desert, and the valley of the Bulunzir-gol. To this great swelling, which arches up between the two border-ranges of the Chol-tagh and Kuruk-tagh, the Mongols give the name of Ghashuun-Gobi or "Salt Desert". It is some 130 to 160 km (81 to 99 mi) across from north to south, and is traversed by a number of minor parallel ranges, ridges and chains of hills. Down its middle runs a broad stony valley, 40 to 80 km (25 to 50 mi) wide, at an elevation of 900 to 1,370 m (2,950 to 4,490 ft). The Chol-tagh, which reaches an average altitude of 1,800 m (5,900 ft), is absolutely sterile, and its northern foot rests upon a narrow belt of barren sand, which leads down to the depressions mentioned above.

The Kuruk-tagh is the greatly disintegrated, denuded and wasted relic of a mountain range which formerly was of incomparably greater magnitude. In the west, between Lake Bosten and the Tarim, it consists of two, possibly of three, principal ranges, which, although broken in continuity, run generally parallel to one another, and embrace between them numerous minor chains of heights. These minor ranges, together with the principal ranges, divide the region into a series of long; narrow valleys, mostly parallel to one another and to the enclosing mountain chains, which descend like terraced steps, on the one side towards the depression of Lukchun and on the other towards the desert of Lop. In many cases these latitudinal valleys are barred transversely by ridges or spurs, generally elevations en masse of the bottom of the valley. Where such elevations exist, there is generally found, on the east side of the transverse ridge, a cauldron-shaped depression, which some time or other has been the bottom of a former lake, but is now nearly a dry salt-basin. The surface configuration is in fact markedly similar to that which occurs in the inter-mount latitudinal valleys of the Kunlun Mountains. The hydrography of the Ghashiun-Gobi and the Kuruk-tagh is determined by these chequered arrangements of the latitudinal valleys. Most of the principal streams, instead of flowing straight down these valleys, cross them diagonally and only turn west after they have cut their way through one or more of the transverse barrier ranges. To the highest range on the great swelling Grumm-Grzhimailo gives the name of Tuge-tau, its altitude being 2,700 m (8,858 ft) above the level of the sea and some 1,200 m (3,937 ft) above the crown of the swelling itself. This range he considers to belong to the Choltagh system, whereas Sven Hedin would assign it to the Kuruk-tagh. This last, which is pretty certainly identical with the range of Kharateken-ula (also known as the Kyzyl-sanghir, Sinir, and Singher Mountains), that overlooks the southern shore of the Lake Bosten, though parted from it by the drift-sand desert of Ak-bel-kum (White Pass Sands), has at first a west-northwest to east-southeast strike, but it gradually curves round like a scimitar towards the east-northeast and at the same time gradually decreases in elevation. In 91° east, while the principal range of the Kuruk-tagh system wheels to the east-northeast, four of its subsidiary ranges terminate, or rather die away somewhat suddenly, on the brink of a long narrow depression (in which Sven Hedin sees a northeast bay of the former great Central Asian lake of Lop-nor), having over against them the écheloned terminals of similar subordinate ranges of the Pe-shan (Boy-san) system (see below). The Kuruk-tagh is throughout a relatively low, but almost completely barren range, being entirely destitute of animal life, save for hares, antelopes and wild camels, which frequent its few small, widely scattered oases. The vegetation, which is confined to these same relatively favoured spots, is of the scantiest and is mainly confined to bushes of saxaul (Haloxylon), anabasis, reeds (kamish), tamarisks, poplars, and Ephedra

European exploration up to 1911

The Gobi had a long history of human habitation, mostly by nomadic peoples. By the early 20th century the region was under the nominal control of Manchu-China, and inhabited mostly by Mongols, Uyghurs, and Kazakhs. The Gobi desert as a whole was only very imperfectly known to outsiders, information being confined to the observations which individual travellers had made from their respective itineraries across the desert. Amongst the European explorers who contributed to early 20th century understanding of the Gobi, the most important were:

• Jean-François Gerbillon (1688–1698)
• Eberhard Isbrand Ides (1692–1694)
• Lorenz Lange (1727–1728 and 1736)
• Fuss and Alexander G. von Bunge (1830–1831)
• Hermann Fritsche (1868–1873)
• Pavlinov and Z.L. Matusovski (1870)
• Ney Elias (1872–1873)
• Nikolai Przhevalsky (1870–1872 and 1876–1877)
• Zosnovsky (1875)
• Mikhail V. Pevtsov (1878)
• Grigory Potanin (1877 and 1884–1886)
• Count Béla Széchenyi and Lajos Lóczy (1879–1880)
• The brothers G. E. Grumm-Grshimailo (1889–1890) and ? Grumm-Grshimailo.
• Pyotr Kuzmich Kozlov (1893–1894 and 1899–1900)
• Vsevolod I. Roborovsky (1894)
• Vladimir Obruchev (1894–1896)
• Karl Josef Futterer and Dr. Holderer (1896)
• Charles-Etienne Bonin (1896 and 1899)
• Sven Hedin (1897 and 1900–1901)
• K. Bogdanovich (1898)
• Ladyghin (1899–1900) and Katsnakov (1899–1900)