LANDFORMS AROUND THE WORLD
Landforms are result of combined work of erosion and deposition. Running water, ground water, wind, glaciers, waves remove fragments of soil, regolith, and bedrock from the parent rock mass. Deposition is the process of dumping this material elsewhere.
Mountains are natural elevation than the surrounding area on the earth surface. Generally, their base is broad and summit is small.
Mountains are grouped in the following categories:
- Fold Mountains
They are mountains formed mainly by the folding on layers within the upper part of the Earth’s crust.
|Himalayas||· It is a mountain range in Asia, separating the plains of the Indian subcontinent from the Tibetan Plateau||· Mount Everest|
|Alps||· It is the greatest mountain range of Europe.||· Mont Blanc|
|Andes||· It running along South America’s western side is among the world’s longest mountain ranges.||· Aconcagua, Argentina|
|Rocky Mountains||· It is a major mountain range located in western North America.||· Mount Elbert|
|Urals Mountains||· It is a mountain range that runs approximately from north to south through western Russia, from the coast of the Arctic Ocean to the Ural River and north-western Kazakhstan.||
· Mount Narodnaya
- Block Mountains
They are formed when large areas are broken and displaced vertically. The uplifted blocks are termed as horsts and the lowered blocks are called graben.
|Vosges||· It is a range of low mountains in eastern France, near its border with Germany.||· Grand Ballon|
|Black Forest Mountains||· It is a mountainous region in southwest Germany, bordering France.||· Feldberg|
|Sierra Nevada||· It is a mountain range in the Western United States, between the Central Valley of California and the Great Basin.||
· Mount Whitney
- Volcanic mountains
- They are formed due to volcanic activity.
- Some examples of residual mountains are Mount Mauna Loa in Hawaii Islands, Mount Popain Myanmar, Vesuvius in Italy, Cotopaxi in Ecuador and Fuji Yama in Japan.
- Residual Mountain:
- These Mountains are left over of old mountains. They are degraded or eroded by winds, rain, frost and running water.
- Some examples of residual mountains are the Sierras of central Spain, Mesas of USA, and Indian Hills like Nilgiris, the Parasnath, the Rajmahal and the Aravalis of north-west India .
- Plateaus are also elevated land but are flat from top like table. That means they are land standing above the surrounding area.
- Their sides may have steep slopes.
- The height of plateaus ranges from few hundred metres to several thousand metres.
- Plateaus also may be young or old.
Plateaus are classified into following categories:
- Intermontane Plateaus:
- These plateaus border fold mountain range from all or less sides.
- Tibet is surrounded by Himalaya, Karakoram, Kunlun, Tien Shah on its two sides.
- The plateau of Colorado, Mexico, Bolivia and Iran are other examples of intermontane plateau.
- Piedmont Plateaus:
- This type of plateaus is bounded with the mountains from one side and with a plain or an ocean on other side.
- Plateau of Malwa in India is a good example of piedmont plateau .
- Continental Plateaus:
- This type of plateaus is formed on a huge area.
- Plateau of Maharashtra in India, Snake River Plateau in North West USA etc are examples of continental plateau.
- Plains are large flat land with an elevation of not more than 200 metres above mean sea level.
- Plains may be extremely level or a little rolling and undulating.
- Most of the plains are formed by rivers and their tributaries.
There are three types of plain found in the world:
- Structural plains:
- The upliftment of a part of the sea-floor or continental shelf is responsible for the formation of these plains.
- These are located on the borders of almost all major continents. south eastern plain of the United States, central low-lands of Australia etc. are some examples of structural plains.
- Erosional plains:
- The continuous and a long time erosion of all kind of upland led to formation of erosional plains.
- They are also known as peneplain because they are almost plain.
- Examples of erosional plains are the Canadian Shield and the West Siberian plain are.
- Depositional plains:
- They are made up of the deposited material which was eroded by the air, water, glacier, wind etc.
- Plains formed by river deposits are called riverine or alluvial plains.
- The rivers which come down from the slopes of mountains, erode the rocks coming in their way. They carry forward the eroded material. Then they deposit their load consisting of stones, sand and silt along their courses and in their valleys.
- The Indo Gangetic plain of the Indian sub-continent, the Hwang-Ho Plain of North China, the Lombardy Plain of the Po River in Italy and the Ganga-Brahmaputra Delta Plain in Bangladesh are examples of alluvial plains.