Notes For All Chapters Geography Class 9
Since the previous 3 years’ examinations, the factual questions (Very Short Answer Type) have been asking relevant to various physical divisions of India consisting of the following topics :
- Location
- The Himalayan Mountains
- The Northern Plains
- The Peninsular Plateau
- The Indian Desert
- The Coastal Plains
- The Islands.
Location
India has all major physical features of the Earth, i.e., mountains, plains, deserts, plateaus, and islands.
In India, the soil colour varies from place to place as it is formed from different types of rocks.
India has varied physical features whose formation can be explained on the basis of the ‘Theory of Plate Tectonics’.
According to the theory of Plate Tectonics, the seven major and minor plates that form the Earth’s crust keep moving, causing stress and thus leading to folding, faulting and volcanic activity.
The physical features of India can be grouped under the following physiographic divisions:
- The Himalayan Mountains or the Northern Mountains
- The Northern Plains or the Indo-Gangetic Plains
- The Peninsular Plateau
- The Great Indian Desert
- The Coastal Plains
- The Islands
The Himalayan Mountains
The Himalayas are young-fold mountains which are the loftiest and one of the most rugged mountain barriers of the world.
The Himalayas are 2400 km long, 400 km to 150 km wide from Kashmir to Arunachal Pradesh respectively.
The Himalayas have three parallel ranges in the longitudinal extent namely :
- Great or Inner Himalayas also called Himadri.
- Middle Himalayas or Himachal.
- Outer Himalayas or Shiwaliks.
The Himalayas can be divided into four sections :
- Punjab Himalayas – between Indus and Satluj.
- Kumaon Himalayas – between Satluj and Kali.
- Nepal Himalayas – between Kali and the Tista.
- Assam Himalayas (Eastern Himalayas) – Between Tista and the Dibang (Tsangpo).
The Northern Plains
The Northern Plains spread over an area of 7 lakh sq. km, 240 km long and 240 km to 320 km broad.
The rivers that flow to the plains from the mountains are involved in depositional work.
The difference in relief causes the Northern Plains to have four regions.
- Bhabar – Adjacent to the foothills of Shiwaliks, a narrow 8 to 16 km wide belt of pebbles and boulders.
- Bangar – Older alluvial plain which rises above the level of the flood plains.
- Khadar – Newer and younger alluvial of the flood plains deposited by the rivers flowing down the plain.
- Tarai – Lies adjacent to Bhabar region, composed of newer alluvium and is thickly forested.
The Peninsular Plateau
The Peninsular Plateau is the tableland formed due to the breaking and drifting of the Gondwanaland.
The plateau consists of two broad divisions, namely, the Central Highlands and the Deccan Plateau.
The eastward extensions of Peninsular Plateau are locally known as Bundelkhand and Baghelkhand. The Chhota Nagpur Plateau marks the further eastward extension drained by the Damodar river.
The Deccan Plateau, a triangular mass, lies to the south of the river Narmada.
The western and eastern edges of the Deccan Plateau are marked by the Western Ghats and the Eastern Ghats respectively.
The Western Ghats are higher than the Eastern Ghats.
The Malwa Plateau is spread across Rajasthan, Madhya Pradesh and Gujarat and slopes towards the
north.
A distinct feature of the peninsular plateau is the black soil area known as Deccan Trap.
The Indian Desert
The undulating sandy plain covered with sand dunes towards the western margins of the Aravalli Hills is the Indian Desert.
Crescent-shaped dunes called barchans cover large parts of the Indian Desert.
Luni is the only large river that flouts in this region.
The Coastal Plains
The narrow’ coastal strips flank the Peninsular Plateau.
On the west, the coastal strips are divided into Konkan (Mumbai-Goa), Kannada Plain and the Malabar Coast from northern to the southern part.
On the east the coastal strip is divided into Northern Circar and the Coromandel Coast from northern to southern part.
The Islands
The Lakshadweep Islands group in the Arabian Sea is close to Kerala.
The Andaman and Nicobar Islands are the two island groups. Andaman Island consists of 204 small islands. India’s only active volcano, Barren Island is situated here.