Chapter 2: PHYSICAL GEOGRAPHY OF INDIA

Introduction

Indias latitudinal and longitudinal extent is 30°. North-South distance is 3214 km and east west distance is 2933 km. North lies in subtropical and warm temperate region and south lies in tropics.

It is the 7th largest country with 3.28 million sq km and 2.4% of worlds land surface and 17% of the population. It has 6100 km of coast in mainland and 7517 km along with the islands.

Gujarat has the longest coastline and Bangladesh shares the largest border with India. In all there are 7 countries not counting Tibet that India shares a border with.

Indira point in Nicobar Islands is the southernmost tip of India.

Physiography of India

    • Physiography deals with the study of the surface features and landforms of the Earth. On the basis of tectonic history, stratigraphy and physiography, India may be divided into the following four physiographic divisions:
      • The elevated Peninsular region
      • The mighty Himalayas and their associated young folded mountains
      • The Indo-Gangetic-Brahmaputra Plains
      • The Coastal Plains and Islands.


Major Geological Formations of the Peninsular India (about 3600 million years ago)

    • The North Central Highlands: They include First The Aravallis (It is one of the oldest folded mountains of the world). The Great Boundary Fault (GBF) separates the Aravallis from the Vindhyan Mountains. Secondly, Malwa Plateau has two drainage systems, one towards the Arabian Sea (Narmada, and Mahi], and another towards the Bay of Bengal (Chambal, Sind, Betwa and Ken) joining the Yamuna river. Finally the Vindhyan ranges (Maikal Range forms a connecting link between the Vindhyans and the Satpura mountains).
    • The South Central Highlands: It has Bundelkhand and Vindhyachal-Baghelkhand or Vindhyachal Plateau.
    • Chotanagpur plateau: Plateau sprawls over parts of West Bengal, Jharkhand, Chhattisgarh, Odisha and northeastern part of Andhra Pradesh.
    • Meghalaya Plateau and Mikir Hills: Consisting of the Garo, Khasi,Jaintia hills and the outlying Milar and Rengma hills, it is a plateau which has been detached from the Indian Peninsula by the Malda Gap.
    • The North Deccan (Maharashtra Plateau):Plateau of Maharashtra includes the enti re state of Maharashtra, except the Konkan coast and the Sahyadris.
    • The South Deccan
    • The Western Ghats:The Western Ghats or Sahyadris run parallel to the western coast for about 1600 km in the north south direction from the mouth of the Tapi river to Kanyakumari (Cape Camorin). The western slope of Sahyadri is steep while the eastern slope is gentle. These are block mountains formed due to the downwarping of a part of land into the Arabian Sea
    • The Eastern Ghats

Physical Geography

The physical geography of India has four parts:

  1.  Northern mountains.
  2.  Northern plains.
  3.  Peninsular plateau
  4.  Coastal plains.

Northern mountain:

The northern mountain complex contains Himalayas, Trans Himalayas and Purvachal. Himalayas are in north, Hindukush and Sulaiman are in north west and Purvachal in east.

The Himalayas are true mountains. They are formed from the continent – continent plate collision. They have sediments of marine origin. It is not a single range but a series of ranges.

The Himalayas have three ranges namely great Himalayas [Himadri] , middle or lesser Himalayas [Himachal] and outer Himalayas [Shiwaliks].

Types of Himalayas

Greater Himalayas:

  1.  Highest and most continuous mountain range in the world. The Greater Himalayas are almost a contiguous range. The range has very few gaps mainly provided by the antecedent rivers. The Greater Himalayas receive less rainfall as compared to the Lesser Himalayas and the Shiwaliks. Physical weathering is pronounced. Erosion is, however, less effective over the Greater Himalayas as compared to the Lesser Himalayas. Being lofty, they have very little forest area. The Greater Himalayas are about 25 km wide with an average height above 6100 metres
  2.  Crystalline rocks.

Middle Himalayas:

  1.  Less in height and discontinuous. The width of the Lesser Himalayas is about 80 km with an average height of 1300-4600 m. It consists, generally, of un-fossiliferous sediments or metamorphosed crystalline.

Outer Himalayas:

  1. Upliftment of the foothills of the Himalayas. The Shiwaliks extend from Jammu Division of Jammu and Kashmir State to Assam. In width, Shiwaliks vary from 8 km in the east to 45 km in the west with an average elevation of about 900 – 1500 m above sea level. It is not a continuous range. It is broader in the west and narrows down In the east. Between the Shiwaliks and the Lesser Himalayas are longitudinal valleys called Doons / Duns.
  2. They are created due to the alluvial deposit of the Himalayan rivers.

Structure of Himalayas:

  1.  The middle bend is convex shape.
  2.  Second sharp bend is towards southern end.
  3.  Western bend towards Nanga Parbat and eastern towards Namcha Barwa.
  4.  Northern side rests against Tibetan plateau and southern side is covered with snow. Gentle slope on northern side and steep slope on southern side.
  5.  The mountains don’t act as a water divide but allow rivers to cut across. The rate of erosion by rivers is greater than the rate of upliftment of Himalayas.

Western Himalayas

Eastern Himalayas

Lower and gradual slope.

Higher and steep sudden slope.

Located on higher latitudes and so colder

Located on lower latitudes and so warmer

Don’t act as barrier to south west monsoon

Act as barrier to south west monsoon

Shiwaliks are farther

Shiwaliks are closer

                                          TABLE 1: EASTERN AND WESTERN HIMALAYAS

Region – wise division of Himalayas

The Himalayas are divided into five regions:

  1.  Kashmir Himalayas
  2. Karakoram, Ladakh, Zanskar, Pir Panjal and Dhauladhar are the ranges from north to south in that order. It has the largest number of glaciers in India.
  3. Karewa formation – clay, sands from old fertile lands. Surrounded by the Greater Himalayas and the Lesser Himalayas is the Kashmir Valley. Having a height of 1585 m above the sea-level, the total area of the Kashmir Valley is about 4920 sq km. It is a structural longitudinal ‘Dun’. A special feature of the the Vale of Kashmir is the Karewa (lacustrine) deposits consisting of silt, sand and clay. These karewas are mainly devoted to the cultivation of saffron and have orchards of apple, peach, almond, walnut and apricot. Kashmir Himalayas are characterised by high snow covered peaks, deep valleys, interlocked spurs and high mountain passes.
  4.  Lake Wular – largest freshwater lake of India located in Kashmir.

 

  1.  Kumaon Himalayas:The Kumaon Himalayas are connected to Tibet by a number of passes.
  2. Garhwal and Kumaon hills from west to east.
  3. Source of Ganga and Yamuna. Located in Uttarakhand.
  4.  Nepal Himalayas
  5. Tallest section of the Himalayas. .
  6.  Sikkim Himalayas: The highest peaks of the world like Mt. Everest (8850 m), Kanchenjunga {8598 m}, Makalu (8481 m), Dhaulagiri (8172 m), Annapurna (8078 m), Manaslu (8154 m) and Gosainath (8014 m) are situated in this part of the Himalayas. It has very few passes. The passes of Nathu-La and Jelep La (4538 min Sikkim) connect Gangtok (Sikkim) with Lhasa (Tibet, China).
  7.  Assam HimalayasOn the southern border of Arunachal Pradesh, the Himalayas take a southerly turn and the ranges are arranged in a north-south direction. Passing through the states of Arunachal Pradesh (Tirap Division) Nagaland, Marripur, Trip ura, and Mizoram, the Himalayas are locally known as Purvachal. The Purvanchal is joined by the Meghalaya Plateau in the west. The extension of the Myanmar mountain chain continues southward up to Andaman and Nicobar Islands and even up to the Archipelago of Indonesia.

   

Himalaya range isn’t stable like western ghats

Debris, avalanches, landslides occur frequently in the Himalayas as they are techtnically active, made up of sedimentary, unconsolidated or semi consolidated rocks.

They have steep slopes.

Nilgiris slightly techtonically stable and have have hard rocks so land slides are less frequent. However direct rockfall is seen due to steep slopes, heavy rains and mechanical weathering due to temperature and escarpments.

Dun:

When rivers are obstructed by mountains they spread out to form lakes. The lakes dry up when the rivers find paths through the mountains. These dried up lakes are called “duns”. They are found between great and middle Himalayas .

Importance of Himalayas: 

  1. Prevents cold Siberian winds from entering into India.
  2. Himalayas are responsible for rainfall in north east. Also without them there would be no Tibet plateau and India would have been a desert.
  3. They split the sub tropical jet streams into two bringing winter rain to India.
  4. Source of perennial rivers.
  5. Great forest and mineral wealth

 

The Syntaxial Bends of the Himalayas

    • The general east-west trend of the Himalayas terminates suddenly at its western and eastern extremities and the ranges are sharply bent southward in deep knee-bend turns which are called syntaxial bends.
    • The western syntaxial bend is near Nanga Prabat where the Indus has cut a deep gorge.
    • There is a similar hair-pin bend in Arunachal Pradesh where the mountains take a sharp bend from the eastern to southern direction after crossing the Brahmaputra river.

Purvanchal:

The mountains have same orogeny as the main Himalayas . From north to south the mountains are patkai, naga and mizo hills. The elevation decreases from north to south.

Patkai hills – border between Arunachal Pradesh and Myanmar.

Manipuri hills – border between Manipuri and Myanmar. Manipur has loktak lake and Mizoram has molassis basin which are soft unconsolidated deposits.

Andaman and Nicobar islands are extension of eastern Himalayas.

Importance of Himalayas

    • Climatic Influence :The altitude of the Himalayas, their sprawl and extension intercept the summer monsoon coming from the Bay of Bengal and the Arabian Sea. They also prevent the cold Siberian air masses from entering into India. Had there been no Himalayas, the whole of northern India would have been a desert. The Himalayas are responsible for the splitting of the jet streams into two branches, and these in turn, play an important role in the arrival, success and failure of the monsoons in India.
    • Defence :Throughout history, the foreign invaders never entered India from the northern side. Despite modern technology of warfare, the Himalayas have great defence value.
    • Source of Perennial Rivers: Most of the perennial rivers of northern India have their origin in the glaciers, lakes, and springs of the Himalayas.
    • Source of Fertile Soils :The perennial rivers and their tributaries carry enormous quantities of alluvial soils which are deposited in Great Plains of India.
    • Generation of Hydro-electricity:
    • Forest Wealth: There is horizontal zonation of vegetation in the Himalayas. The natural vegetation in the Himalayas varies from the humid tropical to the conifers and alpine pastures. At the higher altitudes are the alpine pastures (margs) used by the tribals for grazing cattle during the summer season.
    • Orchards, minerals, tourism and pilgrimage

Northern plains:

Youngest physiographic feature in India. Depositional flood plain created by Himalayan rivers like Indus, Ganga, Brahmaputra and Yamuna.

Densely populated with 30% of worlds population on 10% of worlds agricultural land.

Part of the northern plains:

  1. Babhar – alluvial fans of rivers with course boulders and not suitable for cultivation.
  2. Khadar – new flood plains with very fertile soil
  3. Bangar – old flood plains with calcerous kanker formation; less fertile
  4. Terai – bad drainage with swampy land.

North plains is divided into four parts:

  1.  Rajasthan plains
  •  Formed west of Indus.
  •  Drained by Luni which is located west of Aravalli
  •  Thar desert is a tropical desert formed due to off shore trade winds and Aravalli range is parallel to south west monsoon so no orographic rains.
  1. Punjab plains
  •  Drained by Ravi, Sutlej, Beas
  •  Khadar plains are present but bad topography causes bad drainage.
  1. Gangetic plains
  2. Assam plains
  •  Drained by Brahmaputra – the largest river of India by volume.

Peninsular plateau:

It is covered by western ghats and eastern ghats and in the north by the central highlands. The Deccan traps were formed when Indian plate flowed over reunion island. The basaltic flow created layer over layer and it looks like steps. It is higher than northern plains.

Aravalli range: one of the oldest mountain range. It has sedimentary, metamorphosized rocks. Sabarmati from eastern side of Aravali merges into Arabian sea.

Vindhyan range: source of many north flowing rivers that meet Yamuna. It represents the water divide of central India. Mahi from north side of Vindhya also is a west flowing river.

Malawa plateau – between Aravalli and Vindhya range.

Satpuda range – has the Amarkantak plateau which is source of Narmada and son.

Narmada and tapti are old rift valleys. Worlds largest freshwater lakes are rift valleys.

Western Ghats: UNESCO World Heritage Site

They are extending from Maharashtra to Kerela. In Maharashtra they are steeper and higher. In Karnataka they are broader. In Kerela they are isolated hills with gaps that allow rain winds to pass through them.

Height of the Western ghats decreases from north to south.

The air parcel that passes over the hills retain energy but as they take longer the droplets precipitate into rain.

Anaimudi is the highest peak in the Deccan.

Eastern Ghats 

Discontinuous range but with lower heights in the mountains. Laterite soil is present. Coromandel coast lies between eastern Ghats and bay of Bengal.

Bay of Bengal has 572 islands out of which 2 main islets are richies and labyrinth island.

Andaman and Nicobar are separated by the 10° channel and Lakshadweep by 11° channel. Barren island in Nicobar is india’s only active volcano.

 

Southern hill complex: 

They are not a part of the western or eastern ghats. From north to south the hills are:

Nilgiri, Palani, Anamalai and Cardamom. Palghat pass between Nilgiri and Anamalai hills.

Nallamala, Javadi too are hill ranges in the south but above the above hills.

The western and the eastern ghats meet at Nilgiri hills.

Solved Question Papers

Q.Consider the following pairs :
Medieval Indian State : Present Region
1. Champaka : Central India
2. Durgara : Jammu
3. Kuluta : Malabar
Which of the above pairs is/are correctly matched? (UPSC CSAT 2015)

A.1 and 2

B.2 only

C.1 and 3

D.3 only

Ans . B

The ninth century saw the rise of a number of hill states in the Himalayas, some of which maintained their identity until recent years, despite their wars with each other and the frequent raids from the men of the plains.

States such as Champaka (Chamba – Himachal Pradesh), Durgara (Jammu), Trigarta (jalandhar), Kuluta (Kulu – Himachal pradesh), Kumaon and Garhwal managed to remain outside the main areas of conflict in the northern plains.

Q.Consider the following rivers :
1. Vamsadhara
2. Indravati
3. Pranahita
4. Pennar
Which of the above are tributaries of Godavari? (UPSC CSAT 2015)

A.1,2 and 3

B.2,3 and 4

C.1,2 and 4

D.2 and 3 only

Ans . D

Left tributaries: Purna, Pranahita, Indravati, Sabari, Taliperu, Wainganga, Penganga, Wardha, Dudhana

Right tributaries: Pravara, Manjira, Pedda Vagu, Manair, Kinnerasani

Chapter Review

Score more than 80% marks and move ahead else stay back and read again!

Q1:Indias latitudinal and longitudinal extent is
1.10
2.20
3.30
4.35

ANS.3

Q2:State that has the longest coastline
1.Telangana
2.Bengal
3.Gujarat
4.Andhra pradesh

ANS.3

Q3:Which is true
1.Khadar is more fertile
2.Bangar has calcerous formations
3.both
4.none

ANS.3

Q4: Which is true?
1.Worlds largest freshwater lakes are rift valleys.
2.Height of the Western ghats decreases from north to south.
3.both
4.none

ANS.3

Q5:Southern hills of India from north to south are
1.Nilgiri, Palani, Anamalai and Cardamom
2.Nilgiri, Anamalai, Palani, and Cardamom
3.Palani, Anamalai and Nilgiri, Cardamom
4.Anamalai and Cardamom, Nilgiri, Palani,

ANS.1

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