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NCERT Class 9 Geography | Chapter 2 | Physical Features of India



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NCERT Class 9 Geography | Chapter 2 | Physical Features of India






Introduction :

  • India has 

    • Varied terrain: India boasts diverse landforms, including plains, hills, mountains, deserts, plateaus, and islands.

    • Plain regions: Characterized by vast stretches of flat land, common in plains-dwelling areas.

    • Hilly regions: Rugged terrain with mountains and valleys predominates in hilly areas.

    • Physical features: India encompasses major physical features found on Earth.

    • Geological aspects: The Peninsular Plateau is one of the ancient and stable landmasses, while the Himalayas and Northern Plains are relatively recent.

    • Himalayan region: Represents a youthful topography with high peaks, deep valleys, and fast-flowing rivers, considered geologically unstable.

    • Northern plains: Formed by alluvial deposits.

    • Peninsular plateau: Comprises 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

    (1) The Himalayan Mountains

    (2) The Northern Plains

    (3) The Peninsular Plateau

    (4) The Indian Desert

    (5) The Coastal Plains

    (6) The Islands



NCERT Class 9 Geography | Chapter 2 | CHAPTER 2 Physical Features of India



The Himalayan Mountains :

  • Geologically young: The Himalayas are structurally fold mountains, stretching over India's northern borders.

  • Orientation and dimensions: They extend in a west-east direction from the Indus to the Brahmaputra, covering about 2,400 km with varying widths and altitudinal variations.

  • Parallel ranges: The Himalayas consist of three parallel ranges longitudinally, with valleys between them.

  • Inner Himalayas (Himadri): The northernmost range, containing the loftiest peaks with an average height of 6,000 meters, composed of granite and perennially snowbound.

  • Lesser Himalayas (Himachal): Located to the south of Himadri, comprising highly compressed and altered rocks with an average altitude of 3,700 to 4,500 meters and prominent ranges like Pir Panjal, Dhaula Dhar, and Mahabharat.

  • Outermost range (Shiwaliks): Composed of unconsolidated sediments, extending over 10-50 km with altitudes between 900 and 1100 meters, covered with thick gravel and alluvium.

  • Longitudinal valleys: Duns, lying between the lesser Himalayas and Shiwaliks, are known for their regional names like Dehra Dun, Kotli Dun, and Patli Dun.

  • Regional divisions: Himalayan regions are demarcated by river valleys, with divisions like Punjab Himalaya, Kashmir Himalaya, Himachal Himalaya, Kumaon Himalayas, Nepal Himalayas, and Assam Himalayas.

  • Eastern extension: Beyond the Brahmaputra, the Himalayas bend southward, forming the Purvachal or Eastern hills and mountains, comprising ranges like Patkai hills, Naga hills, Manipur hills, and Mizo hills.



The Northern Plain :


  • Formation: The northern plain results from the interaction of three major river systems - the Indus, Ganga, and Brahmaputra - along with their tributaries, depositing alluvial soil over millions of years.

  • Characteristics: Spreads over 7 lakh sq. km, densely populated, fertile due to rich soil, adequate water supply, and favorable climate.

  • Division: Western part known as Punjab Plains, dominated by the doabs formed by the Indus and its tributaries originating in the Himalayas.

  • Features: Rivers create depositional features like riverine islands and distributaries due to decreased velocity and silt deposition.

  • Sections: Ganga plain extends from Ghaggar to Teesta rivers, while Brahmaputra plain lies in Assam.

  • Relief features: Despite the common perception of flatness, the northern plains exhibit diverse relief, including bhabar (pebbly belt), terai (wet and swampy region), bhangar (older alluvium), and khadar (younger floodplain deposits).

  • Human impact: Terai, once thickly forested, has been cleared for agriculture and settlement, impacting wildlife. Dudhwa National Park is located in this region.

  • Soil characteristics: Bhangar contains calcareous deposits (kankar), while khadar is fertile and renewed annually, ideal for intensive agriculture.




The Peninsular Plateau :


  • Formation and composition: The Peninsular plateau is composed of old crystalline, igneous, and metamorphic rocks, formed due to the breaking and drifting of the Gondwana land, making it part of the oldest landmass.

  • Divisions: Consists of the Central Highlands and the Deccan Plateau.

  • Central Highlands: North of the Narmada River, including the Malwa plateau, bounded by the Vindhyan range, Satpura range, and Aravalis, with rivers draining southwest to northeast.

  • Chotanagpur plateau: Located further east, drained by the Damodar River.

  • Deccan Plateau: Lies south of the Narmada River, flanked by the Satpura range in the north and extending eastwards with hills like Mahadev, Kaimur, and Maikal.

  • Extensions: Meghalaya, Karbi-Anglong Plateau, and North Cachar Hills in the northeast, separated by a fault from the Chotanagpur Plateau.

  • Ghats: Western Ghats and Eastern Ghats mark the western and eastern edges respectively, with the Western Ghats higher and continuous, causing orographic rain, while the Eastern Ghats are discontinuous and dissected by rivers.

  • Features: Western Ghats include peaks like Anai Mudi and Doda Betta, while Eastern Ghats contain Mahendragiri. Shevroy Hills and Javadi Hills lie southeast of the Eastern Ghats.

  • Soil: Deccan Trap, a distinct feature of the Peninsular Plateau, consists of volcanic rocks responsible for the formation of black soil.

  • Aravali Hills: Located on the western and northwestern margins, extending from Gujarat to Delhi in a southwest-northeast direction.




The Indian Desert:

  • Location: The Indian desert is situated towards the western margins of the Aravali Hills.

  • Characteristics: It is an undulating sandy plain covered with dunes, receiving very low rainfall (below 150 mm per year) and having an arid climate with sparse vegetation.

  • Hydrology: Streams appear during the rainy season but quickly disappear into the sand due to insufficient water flow to reach the sea, with the Luni River being the only major river in the region.

  • Dune types: Barchans (crescent-shaped dunes) are widespread, while longitudinal dunes become more prominent near the Indo-Pakistan boundary.

  • Sightseeing: Visitors to Jaisalmer can observe a group of barchans, a notable feature of the Indian desert landscape.




The Coastal Plain

  • Coastal strips: The Peninsular plateau is bordered by narrow coastal strips along the Arabian Sea in the west and the Bay of Bengal in the east.

  • Western coast: Sandwiched between the Western Ghats and the Arabian Sea, it consists of three sections - Konkan (Mumbai-Goa), Kannad Plain, and Malabar coast.

  • Eastern coast: Plains along the Bay of Bengal are wide and level, known as Northern Circar in the north and Coromandel Coast in the south.

  • River deltas: Large rivers like the Mahanadi, Godavari, Krishna, and Kaveri have formed extensive deltas on the eastern coast.

  • Important feature: Lake Chilika is a significant feature along the eastern coast.




The Islands :

  • Island groups: India has two main groups of islands - Lakshadweep Islands and Andaman and Nicobar Islands.

  • Lakshadweep Islands: Located close to the Malabar coast of Kerala, composed of small coral islands, including Laccadive, Minicoy, and Amindive, renamed Lakshadweep in 1973. Covering a small area of 32 sq km, with Kavaratti island serving as the administrative headquarters. Pitti Island, uninhabited, hosts a bird sanctuary.

  • Andaman and Nicobar Islands: Elongated chain of islands in the Bay of Bengal, extending from north to south. The Andaman Islands are located in the north, and the Nicobar Islands are in the south. They are believed to be an elevated portion of submarine mountains, significant for their strategic importance and rich diversity of flora and fauna. Experience equatorial climate and have thick forest cover.

  • Complementary regions: Each physiographic unit complements the others, enriching the country's natural resources. Mountains provide water and forest wealth, northern plains are agricultural granaries, plateaus store minerals crucial for industrialization, and coastal regions and island groups offer opportunities for fishing and port activities, indicating immense future development possibilities.





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