Classification of Plains, Economic Significance of Plains Part-3

Download PDF of This Page (Size: 350K)

Classification of Plains

On the basis of their mode of formation, plains can be classified into the three types:

Structural Plains: These plains are mainly formed by the uplift of a part of the sea-floor or the continental shelf. These are located on the borders of almost all the major continents. For example, the south-eastern plain of the United States formed by the uplift of a part of the Gulf of Mexico. The structural plains may also be formed by subsidence of areas such as the central low lands of Australia.

Image of Structural Plains

Image of Structural Plains

Image of Structural Plains

Erosional Plains: These plains are formed by continuous and long-time erosion of all sorts of upland. These are also called peneplains which means almost a plain. The Canadian shield and the West Siberian plain are examples of erosional plains.

Depositional Plains: Fragments of soil, regolith, and bedrock that are removed from the parent rock mass are transported and deposited elsewhere to make the depositional landforms. When plains are formed by river deposits, they are termed riverine or alluvial plains. For example, 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.

The deposition of sediments in a lake gives rise to a lacustrine plain. For example, the Valley of Kashmir, and Imphal basin in Manipur in India.

When plains are formed by glacial deposits, they are called glacial or drift plains. For example, the plains of Canada and north-western Europe.

When wind is the major agent of deposition, they are called the loess plains. Loess plains of north-western China are formed by the deposits of loess and air-borne fine dust particles.

Economic Significance of Plains

The plains have influenced the human life in the following ways:

Fertile Soil: The plains generally have deep and fertile soil. Since the plains have a flat surface, the means of irrigation are easily developed on these. These factors have made the plains agriculturally so important that they are often called the food baskets of the world.

Growth of Industries: The rich agricultural resources especially of alluvial plains have helped in the growth of agro-based industries. Since the plains are thickly populated, plenty of labour is available for intensive cultivation and for supplying workforce for the industries.

Expansion of Means of Transport: Since the plains have an even surface it favours the building of roads, airports, and laying down of railway lines.

Centres of Civilization: The plains have been the centres of numerous modern and ancient civilizations. The major river valley civilizations of the world such as the civilizations of the Indus and the Nile Valley have flourished in the plains only. Hence, they are referred to as the cradles of civilization.

Setting-up of Cities and Towns: Easy means of transport on land, the growth of agriculture, and industries in plains have resulted in the setting up and expansion of cities and towns. The most developed trade centres and ports of the world are found in the plains. Rome, Tokyo, Calcutta, Yangon, Varanasi, Paris and other famous cities are situated in the plains. As much as 80% of the world’s population lives in the plains.

In Brief, It Can Be Said That:

The major landforms found on the earth’s surface are the mountains, the plateaus and the plains. Besides, the structure of rocks, the external and internal forces acting on the earth’s surface too play a significant role in the development of these landforms. The landforms on the earth’s surface have influenced human life in different ways. Fertile plains have been formed by the rivers originating in the mountains.

These rivers are perennial source of water for irrigation and other purposes. The plateaus are often described as the storehouse of minerals. Many of the major industries are dependent on the constant supply of these minerals. The density of population is also influenced by the landforms. The plains including some of the valleys located in the mountains are abound with people. Compared to the plains, the mountains and the plateaus have an uneven surface that is why they are generally thinly populated.