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DESERTS
Deserts are areas of land that receive less than 250 mm (10 in) of rain per
year. About 12% of land is covered with desert.
IMPORTANT DESERTS OF THE WORLD
66 1
2
0
N
Turkestan
Desert
NORTH
AMERICA
0
23 1
N
2
EUROPE
Arabian
Desert
NorthAmerican
Desert
Sahara Desert
ASIA
GobiDesert
Taklamakan
Desert
Thar
Desert
AFRICA
00
0
23 1
S
2
Atacama Desert
SOUTH
AMERICA
Great
Australian
Desert
Kalahari Desert
AUSTRALIA
Patagonian Desert
0
66 1
S
2
LARGEST DESERTS
DESERTS
AREA
(sq.km.)
(sq. miles)
Sahara
Arabian
Gobi
Patagonian
Great Victoria
Great Basin
Chihuahuan (Mexico)
Great Sandy
Kara Kum
Sonaran
86,60,000
23,30,000
12,00,000
6,73,000
6,47,000
4,96,000
4,50,000
4,07,000
3,50,000
3,10,000
33,20,000
9,00,000
4,63,000
2,60,000
2,50,000
1,90,000
1,74,000
1,57,000
1,35,000
1,20,000
 THREE TYPES OF DESERTS
(1) Tropical deserts (Hot deserts)
(2) Temperate or Mid-latitude deserts
(3) The Cold deserts
 Principal hot deserts of the world
 North America: The Arizona and Lower
California of the US and the Mexican desert.
 South America: Atacama Desert of northern Chile
 Africa: The Sahara, Kalahari and Namib
deserts
 Asia: The Arabian desert and the Thar
desert of Pakistan and India, Taklamakan desert
of China.
 Australia: Great Australian Desert
 Taklamakan desert is the largest desert in China;
it is in Sikiang Province.
 Gibson, Simpson, Victorian and Great Sandy
desert are together called as Great Australian
Desert.
 Kalahari desert is an inland basin with annual
rainfall averaging less than 50 cm.
 Aborigines of Kalahari desert is called Bushmen, have perfected unique methods to survive
in desert like condition.
 It is situated between the Orange river and
Zambezi river.
 Most of the Kalahari lies in Botswana.
 Atacama desert in northern Chile has almost no
vegetation and is considered as the world’s driest desert.
 Atacama is rich in nitrates (caliche), iodine
and borax.
 The hottest place in the world is Al-Azizhiya,
(Libya) is in the Sahara desert.
 The Arabian desert and the Thar desert of India
and Pakistan are tropical deserts.
 The Thar (or the Great Indian desert) desert begins roughly from the southern edge of the
Punjab and continues through North-Western
Rajasthan upto the Aravalli Range.
? Find the odd man out
(a) Taklamakan desert (b) Gobi desert
(c) Arabian desert
(d) Thar desert
Ans: (d) Gobi desert
 Among them Gobi desert is the only cold desert.
OASIS
 A fertile patch in an arid (dry) area where water is available.
 Livestock is limited in the oasis but most of
the land is under cultivation. Water buffalo,
oxen, donkeys and camels are used as
drought animals and to work the water wheel.
 The houses in the oasis are simple and well
suited to the climate. They are made of sundried bricks made with straw mixed with clay
to give more strength to the bricks.
 Gobi desert is the coldest desert in the world. It
spreads over Mongolia and China.
 Much of the Gobi desert is devoid of vegetation
are practically uninhabited.
 The main difference between temperate deserts
and the tropical deserts is that the temperate
deserts are below freezing point for many months
of the cold season.
 DESERT RECORDS
 The largest desert in the World: Sahara desert.
 Its spreads over nearly 6% of world’s total
land area and 28% of the land area of Africa.
 The highest temperatures in the world are recorded in hot deserts.
? The highest temperature in the world has been
recorded at
(a) Death Valley
(b) Al-Aziziyah
(c) Jacobabad
(d) Iqique
Ans: (b) Al-Aziziyah
 Al-Aziziyah in the northern coast of African
desert has been recorded a temperature of 58.70C.
 Death Valley of USA (the highest temperature
recorded in USA) has recorded 58.40C. Average
rainfall in Death Valley is 38mm per year.
 Jacobabad in the Thar desert section of Pakistan has recorded temperature of 51.70C.
 Driest place on earth is Iqique, Atacama desert.
 Coldest desert in the world: Gobi desert.
 DESERT FEATURES
Weathering caused by strong winds, huge temperature variations between day and night, and occasional fast flowing water, forms distinctive desert
features.
 Wadis: Desert water courses which are
steep sided with a flat floor. They are usually
dry.
 Barkhans: Crescent shaped dunes with two
horns may grow up to 30m (100 ft) high. Barkhans
are always moving.
 Seifs Dunes: They are long ridges of sand
that occur where there is little sand and a powerful wind. They grow up to 215 m (700 ft) high.
 Zeugen: They are parallel, flat topped ridges
with caps of hard, resistant rock perched on
softer rock below.
 Mirages: They occur when a layer of warm
air next to the ground is trapped by cooler air
above.
 Light bends towards the horizontal line of
vision and eventually travels upwards.
 The mirage is an upside down virtual image.
 DESERT VEGETATION
 FARMING IN HOT DESERTS
 Desert and semi desert vegetation is found in
regions where the rainfall is less than 25 cm and
with an average rainfall temperature of 250–270C.
 The vegetation mostly consists of thorny
bushes, acacias, wild berries and babul and kikar.
In India these are found in Rajasthan, Kutch
and Saurashtra in Gujarat, South-Western
Punjab and parts of the Deccan.
 The largest cactus is the giant Saguaro from
the Sonaran desert (Mexico). It can grow to 18 m
(60 ft) high.
 In summer rice, millet, maize are the main grain
crops. Small quantities of sugarcane and cotton
are also grown.
 In winter the same lands are used for growing
crops of wheat, barley, oil seeds, onion and
beans.
 The date palm (Phoenix ductylifera) is the oldest known cultivated fruit tree in the desert.
 The young palm needs to be watered for a
couple of years.
 The Sonaran desert of Mexico is noted for
its fleshy and thorny plants such as giant
Saguaro, Cholla and other varities of cacti and
yuccas.
 The ‘cactus’ has small roots but it sucks water
in great quantities and stores it in its thick body.
 GONE WITH THE WIND
 Harmattan: It is a hot dry, dust laden wind
blowing from Sahara to the Guinea cost. Also
called the doctor, it provide a welcome relief from
damp air of the Guinea lands by increasing the
rate of evaporation with resultant cooling effects.
 Sirocco: A hot local wind blowing from
Sahara desert to Mediterranean.
 The Sirocco winds in Libya is known as
Gibli.
 Khamsin: Hot, dry and dusty winds which
blow across Egypt from April to May.
 Loo: In the plains of northern India and Pakistan sometimes a very hot and dry wind blows
from the west in the months of May and June,
usually in afternoon.
 Its temperature unvariably ranges between
450C and 500C. It may cause sunstroke to people.
Desert farm, using plastic to slow evaporation
in the San Quintin Valley, Mexico
 DESERT SOILS
 Desert soils are those soils which have turned
into sand due to excessive weathering, evaporation and lack of moisture. Strong winds shift
large arid dunes from one place to another.
 If there is some availability of water in the desert
soil, millets are grown there.
 The desert soil is fertile and the hot sun causes
quick growth and ripening.
 MINERALS OF DESERTS
 The deserts have become prominent because of
the valuable minerals they yield.
 The Kalahari desert yields copper and diamonds.
DESERT FOX
Erwin Rommel (18911944) German Field Marshal, renowned for his African desert victories during World War II. His victories earned him promotion to Field Marshal as
wel l as t he n ickn am e
“The Desert Fox”.
GREAT DESERTS
Name
Sahara
Australian Desert
Arabian Desert
Dast-e-Lut
Dast-e-Kavir
Desierto de Sechura
Atacama
Patagonia
Kalahari
Namib
Thar
Negev
Ordos
Takla Makan
Gobi
Kara Kum
Kyzyl Kum
Country/Region
North Africa
Australia
Arabia
Iran
Iran
Peru
North Chile
Argentina
Botswana
Namibia
North-west India
Israel
China
China
Mongolia, China
Turkmenistan
Kazhakhstan,
Uzbekistan
Mohave  South California,
North America
Sonoran  North America,
Mexico
***
Kara Kum and Kyzyl Kum together are known as
the Turkestan desert
***
Rub’al Khali & An-Nafud together called
Arabian desert
***
Dast-e-Kavir and Dast-e-Lut are otherwise called
Barren Desert and Salt Desert respectively.
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 The North American desert has silver, lead,
copper, borax, gold and petroleum.
 The Australian desert yields gold in
Kalgoorlie and Coolgradie area.
 The Atacama desert yields copper and the
Chilean part of it has the world-famous deposits
of nitrates.
 Chiquicamata in the Atacama desert lies the
world’s largest copper mine at a height of 3,000
metres in the deserts.
 In Africa, the main oil producing regions in
the Saharan deserts are Egypt and Libya.
 ETHNIC GROUPS
 The principle ethnic groups of the Sahara are
the Turaregs.
 The Turaregs of the western Sahara desert
are mostly nomadic. They build huts of dried
grass (called zeribar) during hot weather and
build leather tents during cooler weather.
 The inhabitants of the Arabian desert are known
as Bedouins (the dweller of the deserts).
 They are also nomads living in tents and
moving from well to well and pasture to pasture.
 The Bushmen of the Kalahari desert lead a nomadic life and are still at a very primitive stage of
development.
 They can imitate the calls of every wild animals they know.
 The Bindibus of the Australian deserts are some
of the most backward people in the world.
 They know only a few implements like digging
sticks, grinding stones, spears and boomerang.
 Bindibus train young dingo dogs to track
and run down kangaroos and rabbits.
 URBAN CENTERS OF
DESERT AREA
 Cairo, Alexandria, Said and Suez are the important urban centers of Africa.
 Baghdad (capital of Iraq), Basra, Aden (Key to
the Suez), Mecca, Karachi are the important centers of Asia.
 Inqique (Chile), Tocopilla, Lima (Peru) of South
America.
 Phoenix and Diego are in North America.
 Egypt lies within the North African desert belt.
The climate is warm and sunny through out the
year.
THE SHIP OF THE DESERT
 Camel is the dependable means of travel in
the desert and has been optly called ‘The
ship of the desert’.
 It can travel 160 km (100 miles) a day and for
8 days without drinking water.
 It has very tough lips and tongue which enable it to nibble at thorny desert vegetation.
 It has broad feet and tough skin to protect
the soles of its feet.
 It can move easily upon the difficult desert
surfaces of gravel, stone, sand and rock.