On this page, you will find NCERT Class 9 Geography Chapter 2 Notes Pdf free download. CBSE Class 9 Social Science Notes Geography Chapter 2 SST Physical Features of India will seemingly, help them to revise the important concepts in less time.
Physical Features of India Class 9 Notes Social Science Geography Chapter 2
CBSE Class 9 Geography Chapter 2 Notes Understanding the Lesson
1. The land of India displays great physical variation. Different geological periods have influenced her relief. Besides geographical formations, a number of processes such as weathering, erosion and disposition have created and modified the relief to its present form.
2. According to the theory of Plate tectonics, the upper part of the earth has been formed out of seven major and some minor plates. The movement of these plates are classified into three types- convergent boundary, divergent boundary and transform boundary.
3. The oldest landmass was a part of the Gondwana land. The Gondwana land included India, Australia, South Africa, South America and Antarctica as one single landmass.
4. Geologically, the Peninsular Plateau constitutes one of the ancient landmasses on the earth’s surface. The Himalayas and the Northern Plains are the most recent landforms.
5. The physical features of India can be grouped under six physiographic divisions-the Himalayan Mountains, the Northern Plains, the Peninsular Plateau, the Indian Desert, the Coasted Plains and the Islands.
6. The whole mountain system of Himalayas represents a very youthful topography with high peaks, deep valleys and fast-flowing rivers. The Himalayas consist of three parallel ranges in its longitudinal extent-The Great or Inner Himalayas or the Himadri, Himachal or lesser Himalayas and the Shivaliks.
7. Besides the longitudinal divisions, the Himalayas have been divided on the basis of regions from west to east-Punjab Himalayas, Kumaon Himalayas, the Nepal Himalayas and Assam Himalayas.
8. The Brahmaputra marks the easternmost boundary of the Himalayas known as the Purvachal or the eastern hills and mountains. The Purvachal comprises the Patkai hills and Naga hills, Manipur hills and the Mizo hills.
9. The Northern Plains are formed of alluvial deposits. The three major river systems of which the plain have been formed are-the Indus, the Ganga, and the Brahmaputra along with their tributaries.
10. The Northern plains are broadly divided into three sections-The Punjab plains, the Ganga plain and the Brahmaputra plain. These plains have diverse relief features. According to the variations in relief features, they can be divided into four regions.
11. The largest part of the Northern Plains is formed of older alluvium. They lie above the floodplains of the rivers and is known as The newer, younger deposits of the flood plains are called khadar.
12. The Peninsular plateau is composed of igneous and metamorphic rocks with gently rising hills and wide valleys. This plateau consists of two broad divisions, namely, the Central Highlands and the Deccan Plateau. The Deccan Plateau is a triangular landmass that lies to the south of the river Narmada.
13. The Western Ghats and the Eastern Ghats mark the western and the eastern edges of the Deccan plateau respectively. The Western Ghats are continuous and are higher than the Eastern Ghats.
14. The Great Indian desert lies towards the western margins of the Aravali Hills. It is an undulating sandy plain covered with sand dunes. This region receives very low rainfall.
15. The coastal plains of India are located along the Arabian Sea coast in the west and along the Bay of Bengal coast in the east. According to their location to the east or west of the peninsular plateau, they are a called-East coastal plain and West coastal plain.
16. India has two groups of Islands-The Lakshadweep Islands groups and the Andaman and Nicobar Islands. The Lakshadweep Islands groups lie close to the Malabar coast of Kerala and the Andaman and Nicobar Islands are located in the Bay of Bengal.
17. Different physiographic units highlights the unique features of each region. Each region complements the other and makes the country richer in its natural resources.
Physical Features of India Class 9 CBSE Notes Important Terms
Folding: A type of earth movement resulting from the horizontal compression of rock layers by internal forces of the earth along plate boundaries.
Faulting: A crack in the earth’s crust resulting from the displacement of one side with respect to the other.
Gondwana land: It is the southern part of the ancient supercontinent Pangea with Angara land in the northern part.
Tethys: The sedimentary rocks accumulated in the geosyncline.
Duns: The longitudinal valley lying between lesser Himalaya and the Shivaliks.
Alluvium: A deposit of clay, silt and sand left by flowing floodwater in a river valley or delta, typically producing fertile soil.
Doab: The term is made up of two words-‘do’ meaning two and ‘ab’ meaning water.
Distributaries: Branches of rivers that do not return to the mainstream after leaving it.
Terai: A wet, swampy and marshy region.
Kankar: The soil containing calcareous deposits.
Khadar: The newer, younger alluvium of the flood plains.
Bhangar: The older alluvium lying above the flood plains of the rivers and presenting a terrace like feature.
Central Highlands: The part of the Peninsular plateau lying to the north of the Narmada river covering a major area of the Malwa plateau.
Western Ghats: The western edges of the Deccan plateau.
Eastern Ghats: The eastern edges of the Deccan plateau.
Deccan Trap: The black soil area of the Peninsular plateau.
Barchans: Crescent-shaped dunes found in the desert regions.
Dune: A hill of loose sand built by wind or the flow of water.
Konkan: The northern part of the coast.
Kannad plain: The central stretch of level open land.
Coral polyps: Short-lived microscopic organisms, which live in colonies.