Question

How were the Northern Plains formed?

Answer 1

Hint: The fertile Northern Plains have been formed due to the rivers that flow across the area. The area has most of the biggest rivers, their tributaries, and distributaries flowing across it.

Complete answer: From the sedimentary deposits-alluvium, brought by the rivers from the Himalayas by their erosion-the northern plains or the great plains in India were formed.
The plains were formed during the Quaternary period in the Pleistocene and Holocene and are India's most recent geological unit. A marine depression was formed between the mountains and the Indian peninsula by the upheaval of the Himalayas. The detrital material was packed with this marine depression or trough. After the final step of the Siwaliks, the deposition of alluvium from the Himalayas began and has continued until now. These plains rest on Himalayan Piedmont's older Tertiary sediments.
1. The Punjab-Haryana Plain: The part of the plain formed as a result of alluvial deposits by five rivers, namely: the Satluj, the Beas, the Ravi, the Chenab, and the Jhelum. The plain is also known as “the land of five rivers”.
2. The Ganga Plain: The Ganga plain lies in U.P., Bihar, and West Bengal. The plain has been formed due to the depositional work of Ganga and its tributaries like the Yamuna, the Gomti, the Ghagra, the Gandak, the Kosi, etc. Chambal, Betwa, Ken, and Son rivers from the peninsular plateau have also contributed to the formation of the plain.
3. The Brahmaputra Plain: This is also known as Assam plain as it is located in Assam. The entire plain is formed by the Brahmaputra and its tributaries.

Additional information In successive deposits, the plains were formed by layers of various sediments of various sizes. The following are these successive phases:

The Bhabar Belt: This belt was created by the boulders and pebbles produced by the rivers' energetic action. It is situated at the foot of the Siwaliks. Due to the high permeability offered by the pebbles and coarse particles, often the floor of the stream under the earth in this belt.

The Terai Belt This area lies next to the Bhabhar. Smaller particles in this belt are accumulated. Here on the soil, the streams re-emerge, making the area very damp and marshy.

The Bhangar belt It was formed by the older alluvium brought by the rivers during the Middle Pleistocene and is very fertile. This is referred to as the older alluvial belt.

Note:
1. The Punjab-Haryana plain was earlier known as Sapta Sindhu- the land of seven rivers, by the Aryan speaking tribes.
2. The Northern Plain is of great significance as it is home to about half the Indian population.