JAC Class 9th Social Science Notes Geography Chapter 2 Physical Features of India

JAC Board Class 9th Social Science Notes Geography Chapter 2 Physical Features of India

→ Introduction

  • India has practically all the physical features of the Earth like mountains, plains, deserts, plateaus, islands etc.
  • Geologically, the land of India displays great physical variation.

→ Major Physiographic Divisions

  • The physical features of India can be grouped under the following physiographic divisions: (i) The Himalayan mountains, (ii) The Northern plains, (iii) The Peninsular plateau, (iv) The Indian desert, (v) The Coastal plains, (vi) The Islands.

→ The Himalayan Mountains

  • The Himalayan mountains are the major sources of water and forest wealth.
  • The Himalayas are geologically young and structurally fold mountains. They stretch over the Northern borders of India.
  • The Himalayas consists of three parallel ranges in its longitudinal extent: (i) The Great or Inner Himalayas or the ‘Himadri’, (ii) The Middle or lesser Himalayas or The ‘Himachal’ (iii) The Outer Himalayas or The ‘Shiwaliks’.
  • The Himalayas are also divided on the basis of regions from West to East. This demarcation is done by river valleys, i.e. the Indus, Sutlej, Kali, Teesta and Dihang rivers.
  • In the west, the part of Himalayas lying between Indus and Sutlej has been traditionally known as Punjab Himalayas.
  • The part of Himalayas lying between Sutlej and Kali rivers is known as Kumaon Himalayas.
  • The Kali and Teesta rivers demacrate the Nepal Himalayas and the part lying between Teesta and Dihang rivers is known as Assam Himalayas.
  • Purvanchal or the Eastern hills and mountains running through the North-Eastern states are mostly composed of strong sand stones, which are sedimentary rocks covered with dense forest.

JAC Class 9th Social Science Notes Geography Chapter 2 Physical Features of India

→ The Northern Plains

  • The Northern plains are the granaries of the country. They provided the base for early civilisations.
  • 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.
  • The Northern plain is broadly divided into three sections: (i) The Punjab plains, (ii) The Ganga plains, (iii) The Brahmaputra plains.
  • According to the variations in relief features, the northern plains can be divided into four regions:(i) Bhabar, (ii) Terai, (iii) Bangar, (iv) Khadar.
  • The largest part of the Northern plain is formed of older alluvium.

→ The Pfehinsular Plateau

  • The Peninsular Plateau is a tableland composed of the old crystalline, igneous and metamorphic rocks. This plateau consists of two broad divisions, namely, the Central Highlands, the Deccan Plateau.
  • The Western Ghats and the Eastern Ghats mark the western and the eastern edges of the Deccan Plateau respectively.
  • The Western part of the plateau, known as the Deccan Trap, contains black soil of volcanic origin.

JAC Class 9th Social Science Notes Geography Chapter 2 Physical Features of India

→ The Indian Desert

  • The Indian Desert lies towards the western sides of the Aravalli Hills. It is an undulating sandy plain covered with sand dunes.
  • Luni is the only large river in this region.
  • This region receives very low rainfall, i.e. below 150 mm per year.

→ The Coastal Plains

  • The Peninsular Plateau is boardered by stretches of narrow coastal strips, running along the Arabian Sea on the West and the Bay of Bengal on the east.
  • The Western coast consists of three sections (i) The Konkan Coast, (ii) The Kannad Plain (iii)The Malabar Coast.
  • The Eastern Coast consists of the Northern Circar and the Coromandel Coast.

→ The Islands

  • The Lakshadweep islands group lies close to the Malabar coast of Kerala and are composed of small coral islands.
  • The elongated chain of the Andaman and Nicobar islands located in the Bay of Bengal extends from North to  South.

JAC Class 9th Social Science Notes Geography Chapter 2 Physical Features of India

→ Mountain: A mountain is a large landform that rises above the surrounding land in a limited area, usually in the form of a peak.

→ Desert: A large dry area, largely devoid of vegetation for want of rain or water.

→ Plateau: A wide, flat, topped area, rising abruptly from the surrounding low-lying area or a water body.

→ Island: A piece of land that is completely surrounded by sea, a river or lake.

→ Valley: A valley is a low area between hills or mountains typically with a river running through it.

→ Ox-bow lake: A crescent-shaped lake on a river floodplain.

→ Fold Mountains: An upland area, such as the Himalayas or Alps formed by the buckling of the Earth’s crust.

→ Physiography: Shape and relief or geographical features of an area.

→ Glacier: A glacier is a huge mass of ice that moves slowly over land.

→ Tributaries: Streams or small rivers that flow into a larger river.

→ Distributary: A river that originates from a major river. It is formed near the river’s mouth before falling into the sea.

→ Waterfall: A waterfall is an area where water flows over a vertical drop or a series of steep drops in the course of a stream or river.

→ Riverine Islands: Islands on a river.

JAC Class 9th Social Science Notes Geography Chapter 2 Physical Features of India

→ Gondwana land: It was an ancient super-continent located in Southern Hemisphere which included the present-day South America, Africa, Australia snd Antarctica.

→ Bhangar: The older alluvium of the Northern Plain is called the Bhangar.

→ Khadar: The younger alluvium of the floodplains is known as the Khadar.

→ Duns: Narrow valleys found between Shiwaliks and Middle Himalayas.

→ Strait: A narrow stretch of water joining two oceans or large water bodies.

→ Barchans: Barchan also spelled Barkhan, crescent-shaped sand dunes produced by the action of wind an predominantly from one direction.

→ Tectonic Plates: Due to internal heat of the Earth, the currents of the semi-molten rocks move towards the crust, and tear it apart, dividing it into large fragments which are called Tectonic Plates.

→ Tethys: An elongated shallow sea sandwiched between two ancient landmasses.

→ Coral: Coral polyps are short-lived microscopic organisms which live in colonies. They flourish in shallow, mud free and warm waters. They secrete calcium carbonate.

→ Atolls: These are circular or horse-shoe-shaped coral reefs. Lakshadweep is one such type.

→ Gorge: The steep-sided narrow and deep valley of a river formed in its upper course is termed as a gorge. It is also called an I-shaped valley.

JAC Class 9 Social Science Notes

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