Physiography of India-2(Peninsular Plateau, Coastal Plains, Islands)

The Peninsular Plateau is formed due to the breaking and drifting of the Gondwana land and thus making it a part of the oldest landmass. This is one of the oldest and most stable landmasses in India.
It is a tableland composed of old crystalline, igneous and metamorphic rocks.
It is an irregular triangle in the structure extending as Delhi ridge in the north-west, Rajmahal hills in the east, Gir range in the west and Cardamom Hills in the south.
The important physiographic features of this are - block mountains, rift valleys, spurs, bare rocky structures, a series of hummocky hills and wall-like quartzite dykes offering natural sites for water storage.
It has undergone recurrent phases of upliftment and submergence accompanied by crustal faulting and fractures.
On the basis of relief features, the peninsular plateau is divided into three broad groups –
The Deccan Plateau
The Central Highlands
The North-eastern Plateau

The Deccan Plateau is a triangular landmass that lies to the south of R. Narmada.
It is bordered by the Western Ghats in the west, the Eastern Ghats in the east and the Satpura, Maikal and Mahadeo range in the north and north-eastern part.
An extension of the peninsular plateau is also visible in the north-east known as Karbi-Anglong Plateau and North Cachar Hills.
The Deccan Plateau is higher in the west and slopes gently eastwards.
Western and Eastern Ghats are prominent features of the Deccan plateau, the comparison between these two ranges are mentioned in the following table

S. NO.	WESTERN GHATS	EASTERN GHATS
1.	They are continuous and can be crossed only through passes.	They are discontinuous and irregular
2.	Average Elevation – (900 – 1600)m	Average Elevation – 600 m
3.	The altitude increases from north to south	The altitude has no general pattern
4.	Important Hills – Nilgiri, Anaimalai, Cardamom, Babubudan, etc.,	Important Hills – Javadi, Palkonda, Nallamala, Mahendragiri, etc.,
5.	Important Peaks – Anaimudi (highest), Doda Betta (Ooty), Kodaikanal etc.	Important Peaks – Mahendragiri (highest) etc.
6.	Most of the peninsular rivers originate here and acts as a water divide between west-flowing and east-flowing rivers.	They are dissected by major rivers like Mahanadi, Godavari, Krishna, Cauvery, etc., which are draining into the Bay of Bengal

The Central Highlands is a part of Peninsular Plateau lying north of R. Narmada covering a major area of Malwa plateau, Vindhyan Range covers the southern extent and Aravalis in the north-west.
The Central Highlands are wider in the west and narrower in the east.
The plateaus like Bundelkhand, Bagelkhand, Chotanagpur makes the eastern extension of the central highlands.
The general elevation ranges between 700-1000 m and slopes towards north and north-eastern directions
This region has undergone metamorphic processes in its geologic history, which can be corroborated by the presence of metamorphic rocks such as marble, slate, gneiss, etc.,
Most of the ranges in this region are examples of relict mountains which are highly denuded and form discontinuous ranges (example: Satpura Range).

It is an extension of the main peninsular plateau and it is believed that due to the force exerted by the north-eastward movement of the Indian plate at that time of the Himalayan origin a huge fault has been created between the two sides and later got filled up by the depositional activities of the rivers.
This region consists of many plateaus like Meghalaya Plateau, Karbi Anglong Plateau, etc.,
This plateau is rich in mineral resources and receives maximum rainfall from the southwest monsoon.
Important Hills – Khasi, Garo, Jaintia, etc.,

The Great Indian Desert lies in the north-western region of the country.
This region receives low rainfall below 15cm per year and resulted in the arid climate with low vegetation cover – thus this desert region also known as
The prominent desert features are – Mushroom Rocks, Shifting Dunes and Oasis.
It is a land of undulating topography dotted with longitudinal dunes and Barchans.
Most of the rivers in this region are ephemeral. Example: R. Luni
Low precipitation and evaporation make it a water-deficit region.
The desert can be divided into two regions: The northern part sloping towards Sindh and the Southern part towards the Rann of Kachchh.

The Peninsular plateau is covered by marine water in 3 sides: the Indian Ocean in the South; the Bay of Bengal in the east and the Arabian Sea in the West.
The extent of coastline in the country is 6100 km in the mainland and 7517 km in the entire geographical coast of the country (including Islands).
On the basis of the location and active geomorphological processes, it can be broadly divided into two: the Western Coastal Plains and the Eastern Coastal Plains.

S. NO.	WESTERN COASTAL PLAINS	EASTERN COASTAL PLAINS
1.	It is an example of submerged coastal plain	It is an example of emergent coastal plain
2.	Western coastal plain is narrower	Eastern coastal plain is broader
3.	They are divided into Kathiawar coast, Konkan coast, Goan Coast and Malabar coast	They are divided into Northern Circar in the north and Coromandel coast in the south
4.	The rivers flowing through this doesn’t form any delta	Well developed deltas can be seen here eg. Krishna – Godavari delta
5.	Provides natural conditions for the development of harbours. Example – JNPT, Mumbai.	Most of the ports in this coastal plain are artificial in nature. Example – Chennai Port

Besides the vast physical features in the mainland of the country, there are two major island groups located in both sides of the peninsular plateau.
The island groups provide the site for Fishing and Port activities.
Though more than 4000 islands are present in Indian territory Andaman and Nicobar and Lakshadweep are the two major island groups.

ANDAMAN & NICOBAR ISLANDS

The Andaman and Nicobar Islands are the chain of islands in the north-south extent located in the Bay of Bengal.
This island group is bigger in size and are more numerous and scattered.
These islands are the elevated portion of the Submarine Mountains.
The entire group of islands are divided into two: Andaman in the north and Nicobar in the South. These two islands are separated by Ten Degree Channel.
Many smaller islands are volcanic in origin and Barren Island is the only active volcano in India is situated here.
Duncan's passage lies between south Andaman and Little Andaman.
Important Peaks: Saddle Peak, North Andaman (738 m); Mount Diavolo, middle Andaman (515 m); Mount Koyob, South Andaman (460 m); Mount Thuiller, Great Nicobar (642 m)
The coastal line has some coral deposits and beautiful beaches. As it is close to the Equator it experiences convectional rainfall and equatorial type of vegetation.

Note

THE LAKSHADWEEP ISLANDS

The Lakshadweep Islands group is located in the Arabian Sea, near the Malabar coast.
This group of islands is mainly composed of coral reefs.
Kavaratti Island is the administrative headquarters of Lakshadweep islands.
Minicoy is the largest island in this group.
This island group consists of storm beaches consisting of unconsolidated pebbles, shingles, cobbles, and boulders.

Note