class -9 NCERT Chapter -2 Geography , Physical features of India

 Physical features of India

Our country has practically all major physical features of the earth such as mountains, Plains deserts ,plateau and Islands.

Major physical features of India and how they have been formed

• Different types of rocks :some are very hard like marble and  some are very soft like soap stone.
• The colour of soil varies from one place to the other because soil is formed out of different types of rocks.
• Most of these variations are caused due to differences in rock formations.
• India is a large land mass formed during different zoological periods which has influenced her relief.
•  Besides zoological formations, a number of process, such as weathering erosion and deposition, have created and modified the relief to its present form.
• Plausible theory is the 'theory of plate tectonics'. According to this theory,   The crust (upper part) of the earth has been formed out of 7 major and some minor plates.
• The movement of the plates results in the building up of stresses within  the plates and the continental rocks above, leading to folding, faulting and volcanic activity.
• Broadly ,these plate Mountains are classified into three types
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1. some plates come towards each other and from convergent boundary.
2.  some plates move away from each other and form divergent boundary .In the event of two plates coming together they may be either collide or crumble or one May slide under the other.
3.  At the times , they may also move horizontally past each other and form transform boundary .

• the mountain of these plates have changed the position and size of the continents over millions of years such movement have also influenced the evolution of the present landform features of India.
• The oldest landmass, (the Peninsula part ) was a part of the gondwana land.
• The gondwanaland included India , Australia ,South Africa ,South America and Antarctica as one single land mass.
• The convectional currents split the correct into a number of Pieces, thus leading to the drifting of the Indo - Australian plate after being separated from the gondwana land, towards north
• The northward drift resulted in the collision of the plate with the much larger Eurasian plate, due to this collision,  the sedimentary rocks which were accumulated in the geosyncline known as the Tethys folded to form the mountain system of Western Asia and Himalaya.
• The Himalaya uplift out of the Tethys sea and subsidy ends of the northern flank of the peninsular plateau resulted in the formation of a large basin.
• In due course of time this depression, gradually got filled with deposition of sediments By The Rivers following from the mountains in the north and the peninsular plateau in the south.
• A flat land of extensive alluvial led to the formation of the northern plains of India.
• The land of India displays great physical variations due logically the peninsular plateau constitutes one of the Ancient land masses 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 Mountain form at anus table zone.
•  The whole mountain system of Himalaya represents a very youthful topographic with the high peaks, deep valleys and fast flowing rivers.
•  The northern plains are formed of Alluvial deposits the plateau is composed of igneous and metamorphic rocks with gently rising hills and wide valleys.

Major physiography division

The physical features of India can be grouped under the following physiographic divisions:

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

• The Himalayas Geographicly young and structurally fold mountains stretch over the northern borders of India .
• these mountains ranges Run in a west east direction from the Indus to the Brahmaputra the Himalayas represent the Loftiest is and one of the most rugged mountains barriers of the world.
•  they form an Arc, which covers a distance of about 2400 km there width varies is from 400 km in Kashmir to 150 km in Arunachal Pradesh.
•  the altitudinal variation are greater in the Eastern half than those in the Western half.
•  the Himalaya consists of three parallel ranges in its longitudinal extent of a number of valleys lie between these ranges .
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• the northern -most range is known as the great for inner Himalayas or the Himadri.
•  it is the most continuous range consisting of the law fist peak with an average height of 600 it contains all prominent Himalayan peaks.
• The folds of the great Himalayas are asymmetrical in nature. the core of this part of Himalaya is composed of granite. It is Perennially snowbound and a number of glaciers descend from this range.
• The range lying to the south of the Himadri forms Himachal or lesser Himalaya the ranges are mainly composed of highly compressed and altered rocks altitude varies between 3,700 and 4500 km. and the average width is of 50 km.
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• While the Pri Panjal range forms the longest and the most important range, the Shayla Share and the Mahabharata ranges are also prominent ones. 
• The range consists of the most Valley of Kashmir ,the Kangra and Kullu Valley in Himachal Pradesh .this reason is well known for its hill stations.
• The outermost range of the Himalayas is called Shivaliks. The extend over a width of 10 to 50 km and have an altitude wearing between 900 and 1100 metre .
• these ranges are composed of unconsolidated sediments brought down by rivers from the main Himalaya ranges located further North .
• These valleys are covered with thick gravel and alluvium. the longitudinal Valley line between lesser Himalaya and the shivalika are known as Duns. Dehradun, Kotli dun and patli dun  are some of the well - known Duns. 
• Besides the longitudinal division the Himalayas have been divided on the basis of regions from west to east.
•  These divisions have been the mark created by river valleys. for example the part of Himalayas lying between indus and Satluj has been traditionally known as Punjab Himalaya but it is also known reasonably as Kashmir and Himachal Himalaya from west to east respectively. the part of Himalayas line between Satluj and Kali rivers is known as kumaon Himalayas. 
• The Kali andTeesta demarcate the Nepal Himalayas and the part lying between Teesta and Dihang rivers is known as Assam Himalayas. 
• The Brahmaputra marks the easternmost boundary of the Himalayas. beyond the Dining gorge,  the Himalayas band sharply to the south and spread along the Eastern Boundary of India. they are known as the Purvanchal or the Eastern Hills and mountains .
• These Hills running through the north -eastern state are mostly composed of strong sandstone, which are sedimentary rocks .
• covered with the dense forest the mostly run as parallel ranges and valleys.
•  The Purvanchal comprises the patkai hills, the naga Hills, the Manipur hil
• ls and the Mizo Hills.

The northern plain 

• The northern plain has been formed by the interplay of the three major rivers systems namely- the Indus, the Ganga and the Brahmaputra along with their tributaries .
• This plane is formed of Alluvial soil. the deposition of alluvium in a vast basin line at the foothills of the Himalayas over millions of years, formed their fertile Plains.
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•  It spreads over an area of 700000 square kilometre the plane been 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 agricultural productive part of India.
•  the rivers coming from northern mountains are involved in the depositional work in the lower course due to gentle slope the velocity of the river decrease, is which results in the formation of riverine islands.
•  The rivers in their lower course split into numerous channels due to the deposition of split the channels are known as distributaries.
•  The northern plane is broadly divided into three sections. 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 plane 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 plane is dominated by the doabs.
• The Ganga plain extend between ghaggar and Treets rivers. 
• It is spread over the states of North India, Haryana, Delhi, UP, Bihar And partly Jharkhand and West Bengal to its East ,particularly in Assam lies the Brahmaputra plain.
•  The northern plains are generally described as flat land with no variations in its relief .
• Actually, it is not through these was Plains also have diverse relief features, according to the variations in relief features, the northern plains can be divided into four regions.
•  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 .
•  South of this belt, the themes and river Re- emerge and create a wet, swampy and marshy region known as  terrain. 
• 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 the region.
•  the largest part of the northern plain is formed of older alluvium.
•  It lies above the floodplain of the rivers and present of trees like features.
•  This part is not as bhangar.
•  The soil in this reason contains calcareous deposits, locally known as kankar .
•  The new year younger deposit of the flute planes 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 table and composed of the old crystalline, igneous and metamorphic rocks .
• it was formed due to breaking and drift in of the Gondwana land and thus, making it a part of the oldest land mass.
•  the plateau has broad and Shallow valleys rounded hills .this plateau consists of two broad divisions ,namely, the central Highlands and the Deccan Plateau.
•  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.
•  The further West ward extension gradually merges with the Sandy and Rocky desert of Rajasthan .
• The flow of the rivers draining this reason, namely the Chambal,the Sind,  the Betwa and the ken  is from SouthWest to North East ,thus  indicating the slope. 
•  The central Highlands are wider in the West but narrow in the east .the eastward extension of this plateau are locally known as the Bundelkhand and baghelkhand.
• The ChotaNagar plateau marks the further Eastward extension, drained by the Damodar River.
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•                                                  A Waterfall in Chotanagpur plateau

•  The Deccan Plateau is a triangular landmass  that lies to the south of the river Narmada.
•  The Satpura ranges flanks its broad base in the north, while the Mahadev, the Kaimur Hills and the maikal range from its Eastern extension.
•  The Deccan Plateau is higher in the west and slopes gently Eastwards.
•  An extension of the plateau is also visible in the north-east ,locally known as the meghalaya , Karib - Anglong plateau and North Cachar Hills.
• It is separated by a Fault from the Chhota Nagar plateau.
•  Three prominent Hill ranges from the west to the east are the Garo , the Kashi and The  jaintia Hills .
• The Western Ghats and Eastern Ghats mark the Western and the Eastern edge of the Deccan Plateau respectively.
• Western ghats  lie parallel to the Western coast.
•  They are continuous and can be crossed passes only.
•  The Western Ghats are higher than the Eastern Ghats. their average elevation is 900-1600 m as against 600 metres of the Eastern Ghats and 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 .
• 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. the height of the Western Ghats progressively increases from north to south.
•  The highest peaks include the Anai Mundi (2695 m )and the Doda betta( 2637 m) .
• Mahendra Giri (1501m) is the highest peak in the Eastern Ghats .
• Shevory  Hills  the javadi Hills are located to the south east of the Eastern Ghats.
•  The famous hill station of Udagamandalam  popularly known as Ooty and the Kodaikanal .
• One of the distinct features of the peninsular plateau is the black soil area known as Deccan 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.
•  The Aravali Hills lie on the Western and North Western 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  

• The Indian desert lies towards the Western marines of the Aravalli Hill. 
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• It is an insulating  Sandy plane covered with sand dunes.
•  This region receives very low rainfall below 150mm per year. 
•  It has arid climate with low vegetation cover .
• Streams appear during the rainy season .
• Luni is the only large river in this region .
• Barchans cover large area but longitudinal dunes become more prominent near the Indo Pakistan boundary.

The Coastal plains 

• The Peninsula 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 .
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• The Western costs sandwhiched between the Western Ghat coast  and the Arabian Sea is a narrow plane.
•  It  consists of three section.
•  The north part of coast is called konkan 
• The central stretch called Kannad plan, while 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, while  the southern part is known as coromandel coast. 
• Large river such as the mahanadi,  the Godavari the Krishna and the Kaveri have formed extensive Delta on this coast.
•  Lake Chilka is an important feature along the eastern coast.

The Islands

•  Located the Lakshadweep Island group lying close to the Malabar coast of Kerala .
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• It covers small area of 32 square kilometre.
•  Kavaratti Island is the administrative headquarter of Lakshadweep.
• This  Island group has great diversity of flora and fauna .
• The Pitti Island, which is UninHabited, has a bird sanctuary. 
• The Andaman is the north and the Nicobar is South.
•  It is believed that these islands are an elevated portion of submarine mountains
•  These Island group are of great strategic importance for the country.
•  There is great diversity of flora and fauna in this group of Island too.
•  These Island lie close to equator and experience equatorial climate and has thick forest cover.
•  The mountain are major source of water and forest wealth.
•  The northern plain are the granaries of the country .
• They provide the base of early Civilization .
• The plateau is a storehouse of materials, which has played crucial role  in the industrialization of country .
• The coastal region and Island group provide site for fishing and sport activities.