Plains are large stretches of flat land. Generally, they are not more than 200 metres above mean sea level. Plains are usually very fertile and population settlements are concentrated here. The Indo-Gangetic plains, the Mississippi plain and the Yang-tze plain are some of the famous plains of the world.
Some plains are extremely level. Others may be slightly rolling and undulating. Most of the plains are formed by rivers and their tributaries. The rivers flow down the slopes of mountains and erode them. They carry forward the eroded material. Then they deposit their load consisting of stones, sand and silt along their courses and in their valleys. It is from these deposits that plains are formed.
Generally, plains are very fertile. Construction of transport network is easy. Thus, these plains are very thickly-populated regions of the world. Some of the largest plains made by the rivers are found in Asia and North America. For example, in Asia, these plains are formed by the Ganga and the Brahmaputra in India and the Yangtze in China.
Plains are the most useful areas for human habitation. There is great concentration of people as more flat land is available for building houses, as well as for cultivation. Because of fertile soils, the land is highly productive for cultivation. In India too, the Indo-Gangetic plains are the most densely populated regions of the country.
A plain is an area of lowland, either level or undulating.Defintion
Types of Plains
Based on their mode of formation, plains of the world can be grouped into 3 major types:
- Structural Plains
- Depositional Plains
- Erosional Plains
These are formed by horizontally bedded rocks, relatively undisturbed by the crustal movements of the earth. Examples:
- Russian platform
- Great plains of USA
- Central Lowlands of Australia
These plains are formed by the deposition of materials brought by various agents of transportation like glaciers, rivers & winds.
Plains formed by Rivers:
- Nile delta of Egypt
- Ganga delta
- Plain of North China by Hwang Ho
Plains formed by Glaciers:
- Parts of Holland and northern Germany
- Mid-west USA
- East Anglia England
- Gulf Coast USA
- Coastal Lowlands of Belgium, Netherlands
Plains formed by Winds:
- Deposit very fine particles called as Loess
- Pampas of Argentina
These plains are carved by the agents of erosion. Rains, rivers, ice and wind help to smooth out irregularities in earth’s surface and convert them to low undulating plains. Such plains of denudation are also described as peneplains.
How are the the Plains useful?
- Plains are the most useful areas for human habitation.
- Building houses, construction of transport network, as well as for cultivation is easy.
- In India, the Indo-Gangetic plains are the most densely populated regions.