Qaidam
Encyclopedia
Depression (geology)
A depression in geology is a landform sunken or depressed below the surrounding area. Depressions may be formed by various mechanisms.Structural or tectonic related:...
that occupies a large part of the Haixi Mongol and Tibetan Autonomous Prefecture
Haixi Mongol and Tibetan Autonomous Prefecture
Haixi Mongol and Tibetan Autonomous Prefecture is an autonomous prefecture in northern Qinghai province of Western China. It has an area of and its capital is Delingha...
in Qinghai Province, western China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
. The basin covers an area of approximately 120,000 km2, one fourth of which is covered by saline lakes and playa
Playa
Dry lakes are ephemeral lakebeds, or a remnant of an endorheic lake. Such flats consist of fine-grained sediments infused with alkali salts. Dry lakes are also referred to as alkali flats, sabkhas, playas or mud flats...
s.
Around 35,000 square kilometers, or one third of the basin is desert, which is known in Chinese as Chaidamu Pendi Shamo (柴达木盆地沙漠), i.e. Qaidam Basin Desert.
The Qaidam Basin forms a sort of shelf on the northeast side of the Tibetan Plateau
Tibetan Plateau
The Tibetan Plateau , also known as the Qinghai–Tibetan Plateau is a vast, elevated plateau in Central Asia covering most of the Tibet Autonomous Region and Qinghai, in addition to smaller portions of western Sichuan, southwestern Gansu, and northern Yunnan in Western China and Ladakh in...
. The Tibetan Plateau is at least 14,000 feet above sea level, the Qaidam about 10,000 and Gansu
Gansu
' is a province located in the northwest of the People's Republic of China.It lies between the Tibetan and Huangtu plateaus, and borders Mongolia, Inner Mongolia, and Ningxia to the north, Xinjiang and Qinghai to the west, Sichuan to the south, and Shaanxi to the east...
to the north about 3,000 to 4,000 feet. A low water divide separates the Qaidam Basin proper from that of Qinghai Lake
Qinghai Lake
Qinghai Lake , is a saline lake situated in the province of Qinghai, and is the largest lake in China. The names Qinghai and Kokonor both mean "Blue/Teal Sea/Lake" in Chinese and Mongolian. It is located about west of the provincial capital of Xining at 3,205 m above sea level in a depression...
to the east.
Orographically
Orography
Orography is the study of the formation and relief of mountains, and can more broadly include hills, and any part of a region's elevated terrain...
, the Qaidam Basin is a comparatively low areas in the northeastern part of the Tibetan Plateau
Tibetan Plateau
The Tibetan Plateau , also known as the Qinghai–Tibetan Plateau is a vast, elevated plateau in Central Asia covering most of the Tibet Autonomous Region and Qinghai, in addition to smaller portions of western Sichuan, southwestern Gansu, and northern Yunnan in Western China and Ladakh in...
.
Qaidam is an intermontane basin, i.e. it is surrounded on all sides by mountain ranges.
In the south, the Kunlun Mountains
Kunlun Mountains
The Kunlun Mountains are one of the longest mountain chains in Asia, extending more than 3,000 km. In the broadest sense, it forms the northern edge of the Tibetan Plateau south of the Tarim Basin and the Gansu Corridor and continues east south of the Wei River to end at the North China Plain.The...
separate it from the higher central section of the Tibetan Plateau. In the north, a number of smaller ridges (Shulenanshan, etc) separate the basin from another higher plateau, which is more known for its northern escarpment, the Qilian Mountains; that entire mountain system is often generically known as Nanshan. In the northwest, the Altyn-Tagh
Altyn-Tagh
Altyn-Tagh, Astyn-Tagh, Altun Mountains, Altun Shan or Aerjin Shan Tagh proper is a part of the range south of Lop Nor), is a mountain range in northwestern China that separates the eastern Tarim Basin from the Tibetan Plateau...
separates the Qaidam Basin from the
Kumtagh Desert
Kumtagh Desert
The Kumtag Desert, Kumtagh Desert or Desert of Kum-tag , literally "sand mountain desert" in Old Turkic language , is an arid landform in Northwestern China, which was proclaimed as a national park in the year 2002.-Definitions:1...
of southeastern Xinjiang
Xinjiang
Xinjiang is an autonomous region of the People's Republic of China. It is the largest Chinese administrative division and spans over 1.6 million km2...
.
Minerals and mining
The basin's large mineral deposits caused a great deal of investment interest from 2005.It has reserves of asbestos
Asbestos
Asbestos is a set of six naturally occurring silicate minerals used commercially for their desirable physical properties. They all have in common their eponymous, asbestiform habit: long, thin fibrous crystals...
, borax
Borax
Borax, also known as sodium borate, sodium tetraborate, or disodium tetraborate, is an important boron compound, a mineral, and a salt of boric acid. It is usually a white powder consisting of soft colorless crystals that dissolve easily in water.Borax has a wide variety of uses...
, gypsum
Gypsum
Gypsum is a very soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO4·2H2O. It is found in alabaster, a decorative stone used in Ancient Egypt. It is the second softest mineral on the Mohs Hardness Scale...
, oil
Oil
An oil is any substance that is liquid at ambient temperatures and does not mix with water but may mix with other oils and organic solvents. This general definition includes vegetable oils, volatile essential oils, petrochemical oils, and synthetic oils....
and natural gas
Natural gas
Natural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...
, and several metal
Metal
A metal , is an element, compound, or alloy that is a good conductor of both electricity and heat. Metals are usually malleable and shiny, that is they reflect most of incident light...
s, with the greatest reserves of lithium
Lithium
Lithium is a soft, silver-white metal that belongs to the alkali metal group of chemical elements. It is represented by the symbol Li, and it has the atomic number 3. Under standard conditions it is the lightest metal and the least dense solid element. Like all alkali metals, lithium is highly...
, magnesium
Magnesium
Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...
, potassium
Potassium
Potassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are...
and sodium
Sodium
Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride...
of anywhere in China. Qaidam is also home to the Qarhan Lake, which contains sixty billion tons of salt
Salt
In chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of cations and anions so that the product is electrically neutral...
. There are 22 oilfields, with estimated reserves of 225 million tons, and 6 gasfields, holding 150 billion cubic metres of gas.