India is divided into five physiographic divisions –
The Himalayas
Distance of about 2400 km, width 400 km in Kashmir to 150 km in Arunanchal Pradesh.
Altitudinal variations are greater in the eastern half.
Trans Himalayas / the Tibet Himalayas.
Older then Great Himalayas.
Acts as watershed between rivers flowing south and north.
40 km wide; height up to 5000 meters.
Example: Karakoram, Zarkar and Ladakh range.
Great Himalayas / Himadri / Inner Himalayas.
Himanchal Himalayas / Lesser / Middle Himalayas.
Most rugged mountain system.
Shiwaliks.
Outermost range of Himalayas.
Width: 10-15 km; altitude: 900-1100 m.
Composed of unconsolidated sediments brought down by rivers.
The purvanchal.
After crossing Dihang George, Himalayas take a sudden southward turn.
A series of comparatively low hills in the shape of crescent with its convex side pointing towards the west.
The great Indian plain.
Mainly work of the Indus, the Ganges and the Brahmputra.Largest alluvial tract of the world; length – 3200 km and width 150 – 300 km.
Regional division.
Rajasthan plain / Thar / Great Indian Desert.
Covers west rajasthan and adjoining parts of Pakistan.
Desert is called Marusthali.
Eastern part is rocky, western part is covered with shifting sand dunes locally called Dhrian.
Eastern part upto Aravali is semi arial plain, known as Rajasthan Bagar; drained by seasonal streams creating fertile tracts locally known as Rohi.
Punjab Haryana plain.
Eastern boundary in Haryana is formed by the Yamuna river.
Depositional processes by the rivers continuing since long, has united these doabs; however this mass of alluvial is broken by bluffs, locally known as Dhayas.
Ganga plain. (largest)
According to its geological variations.
Upper ganga plain.
Delimited by 300 m contour in shivaliks in north, Peninsular body in the south, course of Yamuna river in the west and 100 m contour in east.
Middle ganga plain.
Eastern part of UP and Bihar.
Drained by Ghaghara, Gandak and Kosi.
Major units are –
Ganga – Ghaghara doab.
Ghaghara – Gandak doab.
And Gandak – Kosi doab (Mithila plain).
Lower ganga plain.
Some districts of Bihar and whole West Bengal.
In its northern part sediments are deposited by Tista, Jalahaka and Torsa.
Marked by drawn and barren plain, a tract of old alluvial between Kosi – Mahananda corridor in the west and river Sankosh in the east.
Delta formation accounts for rd of this plain. (largest delta in the world)
Large part of the costal deltas is covered by thick inaccessible tidal forests called Sunderbans.
Brahmaputra plain.
Western boundary is formed by Indo-Bangladesh border as well as boundary of lower Ganga plain.
Brahmaputra enters this plain Sadiya and enters Bangladesh near Dhubri.
Large marshy tracts in this region and southern tributaries of Brahmaputra also have meandering course and there are good number of bhils and ox-bow lakes.