PHYSICAL FEATURES OF INDIA
In fact, our country has practically all major physical features of the earth, i.e.,
mountains,
plains,
deserts,
plateaus and
islands.
The land of India displays great physical variation.
Geologically:
The Peninsular Plateau:
Constitutes one of the ancient landmasses on the earth’s surface.
It was supposed to be one of the most stable land blocks.
The Himalayas and the Northern Plains are the most recent landforms.
Himalayas:
From the view point of geology:
Himalayan mountains form an unstable zone.
The whole mountain system of Himalaya represents,
a very youthful topography with
high peaks,
deep valleys and
fast flowing rivers.
Northern Plains
The northern plains are formed of alluvial deposits.
Comparision:
The peninsular plateau is composed of igneous and metamorphic rocks with gently rising hills and wide valleys.
MAJOR PHYSIOGRAPHIC DIVISIONS
The physical features of India can be grouped under the following physiographic divisions (Figure 2.2):
(1) The Himalayan Mountains
(2) The Northern Plains
(3) The Peninsular Plateau
(4) The Indian Desert
(5) The Coastal Plains
(6) The Islands
The Himalayan Mountains
Characteristics:
They are geologically young and structurally fold mountains stretch over the northern borders of India.
Areas:
These mountain ranges run in a west-east direction from the Indus to the Brahmaputra.
Features of Himalayas:
1. Loftiest and rugged mountain barriers
The Himalayas represent the loftiest and one of the most rugged mountain barriers of the world.
2. Form an arc
They form an arc, which covers a distance of about 2,400 Km.
3. Width:
Their width varies from 400 Km in Kashmir to 150 Km in Arunachal Pradesh.
4. Altitude:
The altitudinal variations are greater in the eastern half than those in the western half.
5. Three Ranges of Himalayas:
The Himalaya consists of three parallel ranges in its longitudinal extent.
A number of valleys lie between these ranges.
Great or Inner Himalayas or the Himadri
The northern-most range is known as the Great or Inner Himalayas or the Himadri.
Features:
Continuous range and loftiest peaks
It is the most continuous range consisting of the loftiest peaks with an average height of 6,000 metres.
Important Himalayan Peaks
It contains all prominent Himalayan peaks.
Asymmetrical Fold
The folds of the Great Himalayas are asymmetrical in nature.
The core of this part of Himalayas is composed of granite.
It is perennially snow bound, and
a number of glaciers descend from this range.
Himachal or lesser Himalaya
The range lying to the south of the Himadri forms the most rugged mountain system and is known as Himachal or lesser Himalaya.
Featurers
The ranges are mainly composed of highly compressed and altered rocks.
The altitude varies between 3,700 and 4,500 metres and
The average width is of 50 Km.
While the Pir Panjal range forms the longest and
The most important range,
the Dhaula Dhar and
the Mahabharat ranges are also prominent ones.
This range consists of the famous valley of
Kashmir,
The Kangra and
Kullu Valley in Himachal Pradesh.
This region is well-known for its hill stations.
Shiwaliks:
The outer-most range of the Himalayas is called the Shiwaliks.
They extend over a width of 10-50 Km and have an altitude varying between 900 and 1100 metres.
These ranges are composed of unconsolidated sediments brought down by rivers from the main Himalayan ranges located farther north.
These valleys are covered with thick gravel and alluvium.
The longitudinal valley lying between lesser Himalaya and the Shiwaliks are known as Duns.
Dehra Dun,
Kotli Dun and
Patli Dun are some of the well-known Duns.
The Himalayas have been divided on the basis of regions from west to east.
These divisions have been demarcated by river valleys.
Punjab Himalaya (Kashmir and Himachal Himalaya) - bt Indus and Sutluj:
For example, the part of Himalayas lying between Indus and Satluj has been traditionally known as Punjab Himalaya but it is also known regionally as Kashmir and Himachal Himalaya from west to east respectively.
Kumaon Himalayas
The part of the Himalayas lying between Satluj and Kali rivers is known as Kumaon Himalayas.
Nepal Himalayas
The Kali and Teesta rivers demarcate the Nepal Himalayas and
Assam Himalayas
The part lying between Teesta and Dihang rivers is known as Assam Himalayas.
There are regional names also in these broad
categories.
*Find out some regional names of the Himalayas
Purvachal or the Eastern hills and mountains
The Brahmaputra marks the eastern-most boundary of the Himalayas.
Beyond the Dihang gorge, the Himalayas bend sharply to the south and spread along the eastern boundary of India.
They are known as the Purvachal or the Eastern hills and mountains.
These hills running through the north-eastern states are mostly composed of strong sandstones, which are sedimentary rocks.
Covered with dense forests, they mostly run as parallel ranges and valleys.
The Purvachal comprises:
the Patkai hills,
the Naga hills,
the Manipur hills and
the Mizo hills.
The Northern Plain
The northern plain has been formed by the interplay of the three major river systems, namely —
the Indus,
the Ganga and
the Brahmaputra along with their tributaries.
This plain is formed of alluvial soil.
The deposition of alluvium in a vast basin lying at the foothills of the Himalaya over millions of years, formed this fertile plain.
It spreads over an area of 7 lakh sq. km.
The plain being about 2400 km long and 240 to 320 km broad, is a densely populated physiographic division.
With a rich soil cover combined with adequate water supply and favourable climate it is agriculturally a productive part of India.
The rivers coming from northern mountains are involved in depositional work.
In the lower course, due to gentle slope, the velocity of the river decreases, which results in the formation of riverine islands.
The rivers in their lower course split into numerous channels due to the deposition of silt.
These channels are known as distributaries.
The Northern Plain is broadly divided into three sections.
Punjab Plains
The Western part of the Northern Plain is referred to as the Punjab Plains.
Formed by the Indus and its tributaries,
The larger part of this plain lies in Pakistan.
The Indus and its tributaries —
the Jhelum,
the Chenab,
the Ravi,
the Beas and
the Satluj - originate in the Himalaya.
This section of the plain is dominated by the doabs.
Ganga plain
The Ganga plain extends between Ghaggar and Teesta rivers.
It is spread over North India in:
Haryana,
Delhi,
U.P.,
Bihar,
partly Jharkhand and West Bengal.
Brahmaputra plain
In the East, particularly in Assam lies the Brahmaputra plain.
Characteristics:
The northern plains are generally described as flat land with no variations in its relief. It is not true.
These vast plains also have diverse relief features.
According to the variations in relief features, the Northern plains can be divided into four regions.
Bhabar:
The rivers, after descending from the mountains deposit pebbles in a narrow belt of about 8 to 16 km in width lying parallel to the slopes of the Shiwaliks.
It is known as bhabar.
All the streams disappear in this bhabar belt.
Terai
South of this belt,
The streams and rivers re-emerge and create a wet, swampy and marshy region known as terai.
This was a thickly forested region full of wildlife.
The forests have been cleared to create agricultural land and
to settle migrants from Pakistan after partition.
Locate Dudhwa National Park in this region.
Bhangar
The largest part of the northern plain is formed of older alluvium.
It lies above the floodplains of the rivers and presents a terrace- like feature.
This part is known as bhangar.
The soil in this region contains calcareous deposits, locally known as kankar.
khadar
The newer, younger deposits of the floodplains are called khadar.
They are renewed almost every year and so are fertile, thus, ideal for intensive agriculture.
The Peninsular Plateau
The Peninsular plateau is a tableland composed of the:
Old crystalline,
Igneous and
Metamorphic rocks.
Formation: It was formed due to the breaking and drifting of the Gondwana land and thus,
making it a part of the oldest landmass.
Features:
The plateau has broad and shallow valleys and rounded hills.
This plateau consists of two broad divisions
Central Highlands and
The Deccan Plateau.
Central Highlands
The part of the Peninsular plateau lying to the north of the Narmada river,
Covering a major area of the Malwa plateau, is known as the Central Highlands.
The Vindhyan range is bounded by the
Satpura range on the south and
The Aravalis on the northwest.
Westward Extension: The further westward extension gradually merges with the sandy and rocky desert of Rajasthan.
Rivers Flowing: The flow of the rivers draining this region, namely
the Chambal,
the Sind,
the Betwa and
the Ken
Is from southwest to northeast, thus indicating the slope.
Width: The Central Highlands are wider in the west but narrower in the east.
Eastward extensions: The eastward extensions of this plateau are locally known as the Bundelkhand and Baghelkhand.
The Chotanagpur plateau marks the further eastward extension, drained by the Damodar river.
The Deccan Plateau:
It’s a triangular landmass that lies to the south of the river Narmada.
Satpura Range or Northward Extension:
The Satpura range flanks its broad base in the north,
Eastern extensions: The Mahadev, the Kaimur hills and the Maikal range form its eastern extensions.
Locate these hills and ranges in the Physical map of India.
Features:
The Deccan Plateau is higher in the west and slopes gently eastwards.
An extension of the Plateau is also visible in the northeast, locally known as the Meghalaya, Karbi-Anglong Plateau and North Cachar Hills.
It is separated by a fault from the Chotanagpur Plateau.
Hill Ranges: Three prominent hill ranges from the west to the east are
the Garo,
the Khasi and
the Jaintia Hills.
The Western Ghats and the Eastern Ghats mark the western and the eastern edges of the Deccan Plateau respectively.
Western Ghats:
Western Ghats lie parallel to the western coast.
They are continuous and can be crossed through passes only.
Locate the Thal, Bhor and Pal Ghats in the Physical map of India.
The Western Ghats are higher than the Eastern Ghats.
Their average elevation is 900– 1600 metres as against 600 metres of the Eastern Ghats.
Eastern Ghats:
The Eastern Ghats stretch from the Mahanadi Valley to the Nigiris in the south.
The Eastern Ghats are discontinuous and irregular and dissected by rivers draining into the Bay of Bengal.
average elevation 600 metres
Orographic rain: The Western Ghats cause orographic rain by facing the rain bearing moist winds to rise along the western slopes of the Ghats.
The Western Ghats are known by different local names.
Height: The height of the Western Ghats progressively increases from north to south.
Highest peaks in Western Ghats:
the Anai Mudi (2,695 metres) and
the Doda Betta (2,637 metres).
Highest peaks in Eastern Ghats:
Mahendragiri (1,501 metres)
Shevroy Hills and
The Javadi Hills are located to the southeast of the Eastern Ghats.
Locate the famous hill stations of Udagamandalam, popularly known as Ooty and the Kodaikanal.
Distinct features of the Peninsular plateau:
Is the black soil area known as Decean Trap.
This is of volcanic origin, hence, the rocks are igneous.
Actually, these rocks have denuded over time and are responsible for the formation of black soil.
Aravali Hills:
The Aravali Hills lie on the western and northwestern margins of the Peninsular plateau.
These are highly eroded hills and are found as broken hills.
They extend from Gujarat to Delhi in a southwest-northeast direction.
The Indian Desert:
Lies towards the western margins of the Aravali Hills.
It is an undulating sandy plain covered with sand dunes.
This region receives very low rainfall below 150 mm per year.
It has arid climate with low vegetation cover.
Streams appear during the rainy season.
Soon after they disappear into the sand as they do not have enough water to reach the sea.
Luni is the only large river in this region.
Barchans (crescent-shaped dunes) cover larger areas but longitudinal dunes become more prominent near the Indo-Pakistan boundary.
If you visit Jaisalmer, you may go to see a group of barchans.
The Coastal Plains
The Peninsular plateau is flanked by stretch of narrow coastal strips, running along
the Arabian Sea on the west and
the Bay of Bengal on the east.
The western coast, sandwiched between the Western Ghats and the Arabian Sea, is a narrow plain.
It consists of three sections.
The northern part of the coast is called the Konkan (Mumbai – Goa),
The central stretch is called the Kannad Plain,
The southern stretch is referred to as the Malabar coast.
The plains along the Bay of Bengal are wide and level.
In the northern part, it is referred to as the Northern Circar,
southern part is known as the Coromandel Coast.
Formation of Delta:
Large rivers, such as
the Mahanadi,
the Godavari,
the Krishna and
the Kaveri have formed extensive delta on this coast.
Lake Chilika is an important feature along the eastern coast.
Chilika Lake is the largest salt water lake in India.
It lies in the state of Odisha, to the south of the Mahanadi delta.
The Islands
The country has two groups of islands.
Can you identify these island groups?
Lakshadweep Islands:
Lying close to the Malabar coast of Kerala.
This group of islands is composed of small coral islands.
Earlier they were known as Laccadive, Minicoy and Amindive.
In 1973, these were named as Lakshadweep.
It covers small area of 32 sq km.
Kavaratti island is the administrative headquarters of Lakshadweep.
This island group has a great diversity of flora and fauna.
The Pitti island, which is uninhabited, has a bird sanctuary.
Corals
Coral polyps are short-lived microscopic organisms, which live in colonies.
They flourish in shallow, mud-free and warm waters.
They secrete calcium carbonate.
The coral secretion and their skeletons from coral deposits in the form of reefs:
They are mainly of three kinds:
barrier reef.
fringing reef and
atolls.
The Great Barrier Reef of Australia is a good example of the first kind of coral reefs.
Atolls are circular or horseshoe-shaped coral reefs.
Question:
Which among the given options is/are correct regarding Great Barrier Reef.
a) Specifically located in Austria
b) these are good example of the Atolls kind of coral reefs
Choose the correct answer:
i) a only
ii) b only
iii) Both a and b
iv) None of the above
Ans:
B
Andaman and Nicobar islands
Located in the Bay of Bengal extending from north to south.
They are bigger in size and are more numerous and scattered.
The entire group of islands is divided into two broad categories –
The Andaman in the north and
Nicobar in the south.
It is believed that these islands are an elevated portion of submarine mountains.
*India’s only active volcano is found on Barren island in Andaman and Nicobar group of Islands.
Significance:
These island groups are of great strategic importance for the country.
There is great diversity of flora and fauna in this group of islands too.
These islands lie close to the equator and experience equatorial climate and has thick forest cover.
Unique features of different physiographic units
Each region complements the other and makes the country richer in its natural resources.
The mountains - major sources of water and forest wealth.
The northern plains -
are the granaries of the country.
provide the base for early civilisations.
The plateau - a storehouse of minerals,
which has played a crucial role in the industrialisation of the country.
The coastal region and island groups
provide sites for fishing and port activities.
Thus, the diverse physical features of the land have immense future possibilities of development.
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