DIFFERENT LANDFORMS
A study of land forms is important for understanding their influence upon man's life. It includes the description of the characteristics of various forms of land surface. There are three major land forms - mountains, plateaus and plains:
Mountains: An uplifted portion of the earth's surface is called a hill or a mountain. In our country, a mountain is differentiated from a hill, when its summit or top rises to more than 900 meters above the base. Those with less than this elevation are called hills. Conventionally mountains are divided into four categories namely: folded mountains, block mountains, volcanic mountains and residual mountains.
PRINCIPAL MOUNTAIN PEAKS :-
Name Country Height (in Meters)
Mt. Everest Nepal - Tibet 8850
Mt. Godwin Austin (K2) India (POK) 8611
Kanchanjunga Nepal 8126
Lhotse Nepal 8501
Nanga Parbat India 8126
Annapurna Nepal 8078
Nanda Devi India 7817
Mt. Kamet India 7756
Saltoro India 7742
Gurla Mandhata Tibet 7728
Trich Mir Pakistan 7700
Minya Konta China 7590
Mt. Communism Tajikstan 7495
Muztagh Ata China 7434
Chomo Lhari India - Tibet 7100
Aconcagua Argentina 6960
Ojos del Salado Argentina-Chile 6868
Plateaus:- A plateau is an elevated area generally in contrast to the nearby areas. It has a large area on its top unlike a mountain and has an extensively even or undulating surface. A steep cliff is usually marked along the side of a plateau away from the mountains except in the case of one surrounded by high mountains. It is along this slope that uplift takes place. The rocks of the plateau are layered with sandstones, shales and limestones. It is this arrangement of the strata which gives it a large even surface.
Plains: A plain is a comparatively level surface of land at a low elevation from the sea. Plains are the simplest of land forms and also widespread. The interiors of most of the continents are occupied by plains. While some plains may rise gently inland, others are nearly flat and some others have rolling or even rough surfaces. These differences are generally caused by the different ways in which they were formed. Plains may be formed by internal earth forces and by processes of denudation and deposition. More than one cause may have contributed to the formation of plains.
SOME MINOR LANDFORMS
LAKES :-
Any hollows in the earth's surface filled permanently with water are known as lakes. The lakes occupy about 1.8 per cent of the Earth's surface. The water of lakes may be fresh, brackish or salt but the number of fresh water lakes in the world is the largest. Lakes are found all over the world. Most of them lie above the sea level. The highest large lake known is Titicaca in South America at a height of 3,920 m. The largest in surface area is the Caspian Sea which is really a salt lake, in Asia. The deepest lake is Baikal in Siberia. The Dead Sea is the lowest lake in the world. The Great Lakes of the U.S. and Canada constitute the world's greatest array of large lakes.
LARGE LAKES OF THE WORLD
Name and location Area in sq. km Length in sq. km Maximum depth in metres
Caspian Sea,CIS-Iran 3,94,299 1,199 946
Superior, USA-Canada 82,414 616 406
Victoria, Tanzania-Uganda 69,485 322 82
Aral, USSR (now CIS) 66,457 428 68
Huron, USA-canada 59,596 397 229
Michign, USA 58,016 517 281
Tanganyika,Tanzania-Zaire 32,893 676 1,435
Bailkal, CIS 31,500 636 1,741
Great Bear, Canada 31,080 373 82
Nyasa, Malawi-Mozambique,
Tanzania 30,044 579 706
Great Slave, Canada 28,930 480 614
Chad, Chad-Niger Nigeria 25,760 - 7
Erie-USA-Canada 25,719 388 64
Winnipeg, Canada 23,553 425 62
ISLANDA :-
Islands are masses of land surrounded by water. They may be either in an ocean, sea, river or lake and may be formed in several ways.
Islands are broadly divided into four types namely : [] Continental islands (e.g. Brithish Isles, New Founded Land) [] Oceanic Islands (e.g. St. Helena) [] Tectonic Islands (e.g. Barbados in West Indies) and [] Coral Islands (e.g. Bahamas and Bermuda).
WORLD'S LARGEST ISLANDS
Largest islands Location Area in sq. kms.
Australia Indian Ocean 7618493
Greenland Arctic ocean 2175000
New Guiena West Pacific 789900
Borneo Pacific Ocean 751000
Malagasy Republic Indian Ocean 587041
Baffin Island Arctic Ocean 507451
Sumatra Indian Ocean 422200
Honshu North West Pacific 230092
Great Britain North Atlantic 229849
Victoria Island Arctic Ocean 217290
DESERTS :-
Desert is a part of the Earth's surface i.e., too dry to support plant or animal life and is usually sparsely and inhabited or uninhabited by man. There are four main categories of deserts namely :
- The Hot (Tropical) Deserts : These are the areas of high atmospheric pressure, with rainfall less than 25 cm, high summer temperatures; e.g., the Sahara, Arabian, Thar deserts.
- The Coastal Deserts : These are on the western margins of continents in latitudes 15-30, with cold offshore currents, and low summer temperature; e.g., Atakama, Patagonia, Namib, Kalahari, Mohave deserts.
- The Mid-Latitude Deserts : These are the deserts of continental interiors, with high summer and low winter temperature; e.g., Gobi, Taklamakan, Turkestan, Australian deserts.
- The Ice and Snow deserts : These are the deserts of Polar lands : e.g., the Greenland, the Antarctica.
THE GREAT DESERTS
s.no Desert Country Area (1000 kms)
1. Sahara North Africa 8400
2. Australian Australia 1550
3. Arabian Arabia 1300
4. Gobi Mongolia, China 1040
5. Kalahari Botswana 520
6. Takla-Makan China 320
7. Kara-Kum Turkmenistan 272
8. Thar North-west 260
9. Sonoran USA, Mexico 310
10. Atacama North Chile 180