Definition of Plains: The surface terrain with low relief and relatively flat, regular and gentle slope is called the Plains.
Classification of Plains: In the plains found in the entire world, variations are found in their condition, structure and factors of their formation. For this reason plains are of different types. The formation process of plains takes place mainly by the actions of erosion and deposition.
Considering these two actions as the basis, the plains are classified as follows:
1. Erosional Plains: At the end of the erosion cycle, all the reliefs are converted into plains.
The plains formed by this are divided into the following parts:
(a) River Eroded Plains: The uneven surfaces coming in the path of rivers are made flat by them through erosion, thereby forming the plains.
Hard resistant rock: Monadnock in the form of mound is seen here and there in these plains. Paris and London Basin are the examples of this type of Plains.
(b) Glaciated Plains: Snow – cover prevails on the high mountain peaks and high latitudes. Due to rubbing and friction, the surface beneath the snow gets flat. Glaciated plains are found in Canada, Sweden and Finland.
(c) Wind – Eroded Plains: The rock particles which are soft and broken by mechanical weathering are flown away by the wind. This wind causes the abrasion of the elevated rocks coming in its path. By this action, the Wind Eroded Plain is formed, which is called the Pediplain.
(d) Karst Plains: In the region of lime – rocks, when the surface unevenness ends in J the last stage of the cycle of erosion of underground water, the Karst Plain is formed. Its examples are found in Nainital and Almora of India, in lime regions of Yugoslavia and France.
2. Depositional Plains:
(a) River – Deposited Plains: These plains are formed by the deposition of eroded debris which is carried away by the flowing rivers from high parts to lower parts. According to the context, these plains are called the Piedmont Plains, Flood Plains and Delta Plains. The deltaic plains of the Ganga, Brahmaputra and Nile rivers are highly fertile and densely populated.
(b) Glacio – Fluvial Plains: These plains are formed from the deposition by glaciers. Dense – ceramic plains are formed by the accumulation of pebbles, stones and gravel carried by the glaciers below the snow – line. Outwash plains are formed from the deposition of fine soil by melted water of glaciers.
(c) Loess Plains: These plains are formed from the accumulation of fine soil carried by wind in desert regions. Loess plains are prominent in China, Argentina, Caspian Sea.
(d) Lava – Made Plains: These plains are formed when the lava, ashes, fine rock particles erupted by the volcanic eruption get accumulated at an extensive area. Lava – Made Plains are found in South India.
(e) Lake – Made Plains: When the lake is filled by sediment deposition of rivers, then the accumulated sediments take the form of the fertile plain. When the lake bottom is elevated up due to internal movements, then its water spreads around and the lake bottom turns into the plain. Plain of Hungary, Prairie region of America are Lake – Made Plains.
Importance of Plains:
The importance of the plains can be understood by the following points:
1. About more than 80% population of the world resides in the plains.
2. The plains have played an important role in the rise of many civilizations.
3. The plains are the most suitable place in terms of agricultural processes.
4. The plains are the most suitable in terms of transportation due to their flat structure.
5. These are the ideal place for human activities.
6. They provide an ideal condition in terms of irrigation, pasture, house construction, railway track and roadway etc.
