PPT: Indo-Gangetic Plains | Geography for UPSC CSE PDF Download

 Page 1


Himalayas
Indo- Gangetic Plain
The Peninsular Plateau
Coastal Plains
The Indian Islands
Physical Divisions 
Page 2


Himalayas
Indo- Gangetic Plain
The Peninsular Plateau
Coastal Plains
The Indian Islands
Physical Divisions 
Indo-Gangetic-
Brahmaputra Plain
Page 3


Himalayas
Indo- Gangetic Plain
The Peninsular Plateau
Coastal Plains
The Indian Islands
Physical Divisions 
Indo-Gangetic-
Brahmaputra Plain
Formation of Indo – Gangetic – Brahmaputra Plain
The rivers which were previously flowing into Tethys sea (Before 
Indian Plate collided with Eurasian Plate – continental drift, plate 
tectonics) deposited huge amount of sediments in the Tethys 
Geosyncline. [Geosyncline – a huge depression]
Himalayas are formed out of these sediments which were uplifted, 
folded and compressed due to northern movement of Indian Plate.
Northern movement of Indian Plate also created a trough to the 
south of Himalayas.
Page 4


Himalayas
Indo- Gangetic Plain
The Peninsular Plateau
Coastal Plains
The Indian Islands
Physical Divisions 
Indo-Gangetic-
Brahmaputra Plain
Formation of Indo – Gangetic – Brahmaputra Plain
The rivers which were previously flowing into Tethys sea (Before 
Indian Plate collided with Eurasian Plate – continental drift, plate 
tectonics) deposited huge amount of sediments in the Tethys 
Geosyncline. [Geosyncline – a huge depression]
Himalayas are formed out of these sediments which were uplifted, 
folded and compressed due to northern movement of Indian Plate.
Northern movement of Indian Plate also created a trough to the 
south of Himalayas.
Depositional Activity
During the initial stages of upliftment of sediments, the already existing 
rivers changed their course several times and they were rejuvenated each 
time (perpetual youth stage of rivers {Fluvial Landforms}).
Head ward erosion and vertical erosion of the river valley in the initial stages, 
lateral erosion in later stages contributed huge amount of conglomerates 
(detritus)(rock debris, silt, clay etc.) which were carried downslope.
These conglomerates were deposited in the depression (Indo-Gangetic 
Trough or Indo-Gangetic syncline) (the base of the geosyncline is a hard 
crystalline rock) between peninsular India and the convergent boundary (the 
region of present day Himalayas)
Page 5


Himalayas
Indo- Gangetic Plain
The Peninsular Plateau
Coastal Plains
The Indian Islands
Physical Divisions 
Indo-Gangetic-
Brahmaputra Plain
Formation of Indo – Gangetic – Brahmaputra Plain
The rivers which were previously flowing into Tethys sea (Before 
Indian Plate collided with Eurasian Plate – continental drift, plate 
tectonics) deposited huge amount of sediments in the Tethys 
Geosyncline. [Geosyncline – a huge depression]
Himalayas are formed out of these sediments which were uplifted, 
folded and compressed due to northern movement of Indian Plate.
Northern movement of Indian Plate also created a trough to the 
south of Himalayas.
Depositional Activity
During the initial stages of upliftment of sediments, the already existing 
rivers changed their course several times and they were rejuvenated each 
time (perpetual youth stage of rivers {Fluvial Landforms}).
Head ward erosion and vertical erosion of the river valley in the initial stages, 
lateral erosion in later stages contributed huge amount of conglomerates 
(detritus)(rock debris, silt, clay etc.) which were carried downslope.
These conglomerates were deposited in the depression (Indo-Gangetic 
Trough or Indo-Gangetic syncline) (the base of the geosyncline is a hard 
crystalline rock) between peninsular India and the convergent boundary (the 
region of present day Himalayas)
New rivers and more alluvium
The raising of Himalayas and subsequent formation of glaciers gave rise to many new 
rivers. These rivers along with glacial erosion {Glacial Landforms}, supplied more alluvium 
which intensified the filling of the depression.
With the accumulation of more and more sediments (conglomerates), the Tethys sea 
started receding.
With passage of the time, the depression was completely filled with alluvium, gravel, rock 
debris (conglomerates) and the Tethys completely disappeared leaving behind a 
monotonous aggradational plain.
During the recent times (since few million years), depositional work of three major river 
systems viz., the Indus, the Ganga and the Brahmaputra have become predominant.
Hence this arcuate (curved) plain is also known as Indo-Gangetic-Brahmaputra Plain.