Class 9 Social Science Physical Features of India Exam Notes. Please refer to the examination notes which you can use for preparing and revising for exams. These notes will help you to revise the concepts quickly and get good marks.
Formation Of Relief/ Physical Feature Of India
India is made up of mountains, Plains, Plateaus, desert and islands etc. The action and reaction of many natural forces above and below the earth’s crust for millions of years went into the formation of the present physical features of India. Some such forces are the earthquakes, the volcanic eruptions, heat of the sun and above all the movement of the tectonic plates etc.
Earth scientists have attempted to explain the formation of physical features with the help of "Theory of Plate Tectonics". According to this theory, the crust (upper part) of the earth has been formed out of seven major and some minor plates.
Tectonic Plates :
Due to internal heat of the earth, the current of the semi-molten rocks begin to move towards the crust and tear it apart dividing it into large fragments, called lithosphere or tectonic plates. There are seven major plates namely, South America, North America, Pacific, Indo Australian, Eurasian, African and Antarctic.
Types of plates :
Tectonic plates are always in the process of moving in one direction or the other. These movements are generally classified into three types –
(A)Diverging Plates : If these plates move away from each other, they are called diverging plates. The boundary they form is called divergent boundary.
(B)Converging Plates : If these plates are pushed together, they are called the converging plates. The boundary they make is called convergent boundary.
(C)Transform Plates : Converging plates sometime neither collide with each nor slide under the other but they move horizontally push each other. Such plates are called the transform plates and boundary they make is called the transform boundary.
Formation of Himalayas :
Geologists have us believe that where now Himalayas stand, once there was a vast sea (called Tethys). All these changes were brought about by the internal movements below the earth crust and external forces operating on the surface of the earth. The formation of Himalayas is also the result of these crystal plates. One of such plates (Indo-Australian plate) separated from the super continent Gondwana land and drifted slowly towards north. It collided with the much larger Eurasion plates about 5 crore years ago. The northern.
edge of the Indo-Australian plate was pushed beneath the Eurasion plate. As a result of the collision of these two plates, the sedimentary rocks of enclosed ocean were folded to form the so-called Himalayas and other mountain system of western Asia and central Asia.
♦ Formation of the Northern Plains :
The Northern plains were formed as a result of the geological formation made during the different geological periods as well as a number of process like weathering, erosion and deposition. The work of weathering of rocks carved out by the stormy winds and the work of erosion and deposition carried out by the mighty rivers over a period of millions of years. The Himalayan uplift out of the Tethys Sea and subsidence of the northern flank of the peninsular plateau resulted in the formation of a large basin. In due course of time this depression, gradually got filled with deposition of sediments by the river flowing from the mountains in the north and the peninsular plateau in the south. A flat land of extensive alluvial deposits led to the formation of the northern plains of India.
The work of weathering by winds and of erosion and deposition by the mighty rivers is still going on and consequently the land is slowly and slowly advancing there by pushing the sea bed.
→ MAJOR PHYSIOGRAPHIC DIVISIONS OF INDIA
The major physical or physiographic divisions of India are the following -
1. The Himalayan Mountains
2. The Northern Plains
3. The Peninsular Plateau
4. The Indian Desert
5. The Coastal Plains
6. The Islands
→ THE HIMALAYAN MOUNTAIN
These fold mountains extend from Kashmir to Arunachal Pradesh in the north of India. These mountain ranges run-in a west-east direction form the Indus to the Brahmaputra. Their length is about 2500 km and width varies from 230 to 400 km. The Himalayas have three main divisions or ranges.
(A) The Great Himalayas or Himadri
(B) The Middle Himalayas or the Himachal
(C) Lesser Himalayas or Shivalik Ranges
(A) The Great Himalayas or Himadri : These are those ranges which are always snow capped. These ranges contain several high peaks which exceed 8000 meters above sea level. Mount Everest is the highest peak (8, 848 metres) among them. In addition to that K2 (8, 611) Kanchenjunga (8, 589 meters) Dhaulagiri (8, 172 metres) Nanga Parbat (8, 126) and Annpurna (8, 078 meters) etc are some other high peak. As these ranges remain always covered with snow so they are called, 'The ‘Himadri’. The Himalaya consists of three parallel ranges in its longitudinal extent. A number of valleys lie between these ranges. The core of this part of Himalayas is composed of granite.
(B) The Middle Himalayas or the Himachal : These ranges lie below the great Himalayas. Their altitude varies between 3700 and 4500 meters. There are alternating ridges and valleys among these ranges. The Kathmandu valley in Nepal as well as the Kashmir valley in India are the largest valleys in these regions. The Pir Panjal range in Kashmir also belongs to this part of the Himalayas. The ranges are mainly composed of highly compressed and altered rocks.
(C) The Outer Himalayas or the Shivalik : These are the foot hill ranges of the Himalayas. Their altitude varies between 900 to 1100 metres. These ranges are often discontinue. They have gentle slopes towards the north and step slopes towards the South. These range is made of unconsolidated material such as mud, silt and soft rock and is prone to earth quakes and landslides. Some narrow valleys are found between Shivalik and Himachal. They are called dunes. E.g. Dehradun, Kotli Dun and Patli Dun.
Purvanchal or the Eastern hills and mountains : Beyond the Dihang gorge, the Himalayas bend sharply to the south and spread along the eastern boundary of India. They are known as the purvanchal or the Eastern hills and mountains. These hills running through the northeastern state are mostly composed of strong sandstones which are sedimentary rocks. Covered with dense forests, they mostly run as parallel ranges and valleys. The Purvanchal comprises the Patkai hills, the Naga hills, Manipur hills and the Mizo hills.
On the the basis of the location Himalayas can be divided as follows :
1. Western Himalayas (Punjab Himalayas) : The western section lying between the Indus and the Satluj, covers large parts of Jammu and Kashmir and a part of Himachal Pradesh. They are made up of Ladakh, Zoskar and Pir Panjal ranges.
2. Central Himalayas : The section between the Satluj and Kali is known as Kumayon Himalayas. They extend through the state of Uttaranchal in India and Nepal.
3. Easterm Himalayas : The section between the Kali and Tista is known as the Nepal Himalayas.
4. Assam Himalayas : The section between the Tista & Dihang is known as Assam Himalayas or Purvanchal. They are made of Patkai, Naga and Mizo hills. These hills are mainly composed of strong sand stones.
→ THE NORTHERN PLAINS
The plain has been formed by the interplay of the three major rivers. 1. The Indus 2. The Ganga
3. The Brahmaputra, along with their tributaries. This plain is formed of alluvial soil. It spreads over an area of 7 lakh sq. km. The plain being about 2400 Km long and 240 to 320 km broad, is a densely populated physiographic division. With a rich soil cover combined with adequate water supply and favorable climate it is agriculturally a very productive part of India. The rivers coming from northern mountains are involved in depositional work. In the lower course, due to gentle slope, the velocity of the river decreases which results in the formation of riverine islands. The rivers in their lower course split into numerous channels due to the deposition of silt. These channels are known as distributaries. The vast plain can be sub divided into the following :
(A) The Indus River Basin : This region is drained by the Indus and its tributaries the Jhelum, Chenab, Beas, Ravi and Satluj. River Satluj also rises in the himalayas. The water of these rivers flow into the Arabian Sea. The Punjab Plains are formed by the five main tributaries of the Indus and hence the name ‘Punjab’ meaning the land of five rivers. This section of the plains is dominated by the doabs.
(B) The Ganga Brahamputra Basin : The Ganga enters the northern Plains at Haridwar and flows eastward. On its way to the sea, it is joined by the number of tributaries both from north and south. It is joined by the Brahamputra in Bangladesh, which enters India in Arunachal Pradesh. Flowing south for a while the Brahmaputra turns west and across Assam. Upon reaching Bangladesh, it turns south again. The joint stream of the Ganga and Brahamaputra flows by the name of Meghna and drains into the Bay of Bengal. The Ganga Brahmputra Delta (the Sunderbans) is the world’s largest and the fastest growing delta.
On the basis of the differences in the relief, the plain is divided into (1) Bhabar (2) Tarai (3) Bhangar (4) Khadar.
(1) Bhabar : It is narrow belt covered with pebbles lies along the foot of the Shiwaliks from the Indus to the Tista. They are laid down by numerous streams descending down the Hills. The pebbled beds are parallel to the slope of the river bed. This belt is about 8 to 16 k.m. in width.
(2) Tarai : South of Bhabar belt, the streams and rivers reemerge and create a wet and marshy area. It has a thick forest and a variety of wild life.
(3) The Bhangar : It is composed of old alluvium. It is formed higher up in the plains of rivers and present a ressace like feature. It is less fertile as compared to Khaddar. The soil in this region contains calcareous deposits called kankar.
(4) Khaddar : It is composed of new alluvium. It is formed in the lower levels in the plains near the river. It is very fertile as they are renewed almost every year. It is ideal for intensive agriculture.
♦ Importance of Northern Plains :
1. With their fertile alluvial soils, flat surface, slow moving perennial rivers and favourable climate, the Great plains of North India are of great economic and social significance.
2. The fertile soil and assured water resources have made these plains a rich agricultural land. These plains are the granaries of India.
3. The plains have a good network of roads and railways which has led to large scale industrialization of the region.
4. As the region has sufficient employment opportunities, so density of population is high.
5. The Northern plains is the site where the Ancient civilization of Mohenjodaro and Harappa developed.
→ THE PENINSULAR PLATEAU
To the south of the Ganga plain of northern India lies the extensive peninsular plateau. This plateau covering nearly half of the area of India is triangular in shape with a broad base in the north and a narrow apex in the south. The peninsular plateau is made up of ancient igneous and metamorphic rocks. It is the oldest part of the Indian sub continents. It was formed due to the breaking and drifting of the Gondwana land and thus, making it a part of the oldest landmass. The plateau has broad and shallow valleys and rounded hills. One of the distinct features of the peninsular plateau is the black soil area known as Deccan Trap. This is of volcanic origin hence the rocks are igneous. Actually these rocks have denuded over time and are responsible for the formation of black soil. The Aravali Hills lie on the western and northwestern margins of the peninsular plateau. These are highly eroded hills and are found as broken hills. They extend from Gujarat to Delhi in a southwest-northwest direction. The plateau has an undulating surface with gentle slopes. This plateau is divided by the Narmada river into two parts.
(A) The Central Highlands
(B) The Deccan Plateau.
The boundary between these two units is formed by the Vindhya Range.
The Central Highlands :
The part of the Peninsular plateau lying to the north of the Narmada river covering a major area of the Malwa plateau is known as the Central Highlands. The Vindhaya range is bounded by the Central Highlands on the south and the Aravallis on the northwest. The further westward extension gradually merges with the sandy and rocky desert of Rajasthan. The flow of the rivers draining this region, namely the Chambal, the Sind, the Betwa and Ken is from southwest to northeast, thus indicating the slope. The Central Highlands are wider in the west but narrower in the east. The eastward extensions of this plateau are locally known as the Bundelkhand and Baghelkhand. The Chotanagpur plateau marks the further eastward extension drained by the damodar river. The highest peak of the peninsular region, Anai Mudi (2695 metres above the sea level) is situated in the state of Kerala. It is the highest peak of the Annamalai hills.
The eastern edge of the Deccan Plateau is marked by the Eastern Ghats. Unlike the Himalayas, which have sharp lofty peaks, the hills of peninsular region are low and they do not have high peaks.
A large number of rivers flow through the deccan Plateu region. The river Narmada, flowing through a narrow rift valley between the Vindhyas to the north and Satpuras to the south, separates the Deccan Plateau from the Malwa Plateau. To the south of Satpura range, flows the Tapi. Like Narmada, this river also flows into the Arabian sea. Both Narmada and Tapi do not form any delta. The other major rivers of the Deccan Plateau including the Mahanadi, Godavari, Krishna and Kaveri, flow into the Bay of Bengal. All these rivers make their deltas near the cost. The Godavari is the longest among the rivers of the Deccan plateau.
One of the distinct features of the Peninsular plateau is the Deccan Trap. The Deccan trap has been formed due to the continuous oozing of the lava from the interior of the earth.
The Northeastern Plateau :
The Northeastern plateau is an extension of the Deccan Plateau in the northeast-locally known as the Meghalaya and KabiAnglong Plateau. It is separated by a fault from the Chotanagpur Plateau. Three prominent hill ranges from the west to east are the Garo, the Khasi and the Jaintia Hills.
→ THE COASTAL PLAINS OF INDIA
On the western and the eastern margins of the Deccan Plateau, stretch the western and the eastern coastal Plains respectively.
1. The Western Coast : It consists of three sections.
(A) Konkan (B) Kannad (D) Malabar
The northern Part of the Western coastal plain in Maharashtra and Karnataka is called Konka n Coast.
The sourthern part of this plain is called the Malabar coast. A large number of back waters called lagoons are found along the Kerala coast. Only few large rivers like the Narmada, Tapi and Mahi flow through it. The plain along the Bay of Bengal are wide and level. In the northern part, it is referred to as the Northern Circar, while the sourthern part is known as the Coromanal Coast. Large rivers such as the Mahanadi, the Godavari the Krishna and the Kaveri have formed extensive delta on this coast. Lake Chilka is an improtant
feature along the eastern coast.
→ THE GREAT INDIAN DESERT
1. It lies to the west of the Aravali Range.
2. It occupies a major part of the state of Rajasthan and extends upto Sind in Pakistan as the Thar Desert.
3. The land is generally sandy and covered with sand soil.
4. The region is dry with hardly any rivers.
5. Luni is the only river in this region.
→ THE ISLAND GROUPS
1. Lakshdweep and Andman and Nicobar Islands are the main Islands of India.
2. Lakshdweep is located 300 km west of the coast of Kerala in the Arabian Sea.
3. The Lakshadweep Islands are a group of 36 islands.
4. The Lakshadweep Islands were formerly known as Laccadive, Minicoy and Amindivie Island. They were renamed Lakshadweep in 1973.
5. The Lakshdweep is the tiniest Union Territory in terms of area.
6. Kavaratti Island is the headquaters of Lakshadweep.
7. Andaman and Nicobar Islands are located in the Bay of Bengal.
8. The southern most point of India, called the Indira Point, is located in the great Nicobar Island.
9. The Andaman and Nicobar Island has as many as 200 Islands.
10. The Nicobar group consists of 19 islands and these Islands are fairly large and more numerous than the Lakshadweep.
11. The Pitli Island, which is unihabited, has a bird sanctury is in Lakshdweep Islands.
12. These Islands are known for their great diversity in terms of flora and fauna.
♦ India as a geographical unit
1. The northern mountains are the major sources of water and forest wealth.
2. The northern plains are the granaries of the country. They provide a base for early civilisations.
3. The plateau is store house of minerals which has played a crucial role in the industrialisation of the country.
4. The coastal region and Island groups provide sites for fishing port activities.
5. Thus the diverse physical features of the land have immense future possibilities of development.
GLOSSARY
1. Tarai Zone : It is a Zone next to the bhabar which is wet and marshy. It has a thick forest cover and a variety of wildlife.
2. Water divide : The upland that separates the flow of two rivers or river system.
3. Delta : It is a triangular deposition of sediment at the mouth of a river. The river become slow at the mouth of the sea, so mud and silt settle down and from the delta.
4. Estuary : It is a narrow deep valley at the mouth of a river where currents or tides are strong or the current of the river itself is swift.
5. Tributary : A river which joins the main river and increase the volume of water.
6. Plate Tectonic : The scientific concept which explains the movements of the different plates of the crust of the earth.
7. Gondawana land : A major portion of the crust which once incorporated Australia, Peninsular India south Africa
and south America.
8. Tethys Sea : A narrow sea with a sinking bottom lying between Gondwana land in the south and Angara land in the north.
9. Flood Plain : A plain formed by the sediment deposited by the rivers years after year.
10. Bar : A deposit of sand or mud in the river channel.
11. Levees : An elevated bank flanking the channel of a river and standing above the level of the flood plains.
12. Lagoon : A salt water lake separated from the sea by the sandbars.
13. Glacier : Slow moving rivers of snow & ice.
14. Pass : A gap in mountain range providing a natural route across.
15. Alluvial Plains : Flat low lying lands made of the alluvium.
16. Diverging plate : Plates which are moving away form each other.
17. Converging Plate : Plates which are coming together.
18. Pernnial Rivers : Rivers which flow through out the year.
19. Fold mountain : The fold mountains formed during the most recent major phase of folding in the earth’s crust.
20. Coral Polyps : Coral polyps are short, lived microscopic organisms which live in colonies.
21. A Distributary : A distributary is that river which originates from a main river. It is formed near the river's mouth before it falls into the sea.
22. Gorge : The steep-sided narrow and deep valley of a river formed in its upper course is termed as a Gorge or a Canyon. It is also called an I – shaped valley. For example : The Brahmaputra gorge (5500m), and the Indus gorge.
23. A Rift Valley : A rift valley is the valley which has been formed as a result of the subsidence (sinking) of the landmass between two blocks due to faulting.
24 Sand dune : A mound ridge, or low hill of loose, windblown sand.
EXERCISE
A. VERY SHORT ANSWER TYPE QUESTIONS
Q.1 Why are Shivaliks prone to landslides ?
Q.2 What are the dunes and where are they found ?
Q.3 What are tectonics plates ?
Q.4 Explain plains are more fertile. Give two reasons.
Q.5 Which continents of today were a part of Godwana land ?
Q.6 Mention the three types of plates movements.
Q.7 Name the oldest landmass of the Indian subcontinent.
Q.8 What was the Gondwana land ?
Q.9 Name the major rivers of the northern India.
Q.10 What is meant by doab ?
Q.11 How is the northern plain divided on the basis of the differences in relief ?
Q.12 What is Tarai Zone ?
Q.13 What is barchan ?
Q.14 Name any two peaks of the Western Ghat ?
Q.15 Name two famous valleys in the state of Himachal Pradesh.
Q.16 Name two rivers which form estuaries ?
Q.17 What are the dunes made up of ? Give an example.
Q.18 What is a water divide ?
Q.19 Name two passes of Eastern Himalayas ?
Q.20 Name the seven major tectonic plates.
Q.21 How is the northern plain divided on the basis of the difference in the relief ?
Q.22 What is the local name of the Western Ghats in :
(i) Maharashtra and Karnataka.
(ii) Along Kerala-Tamil Nadu Border
(iii) Tamil Nadu.
Q.23 Which is the highest peak of the Deccan plateau ?
Q.24 Why are the Northern Plains primarily an agricultural belt ?
Q.25 What is a distributary ?
Q.26 Where do Corals flourish ?
Q.27 What are the three kinds of Corals ?
Q.28 Give an example of the barrier reef kind of coral reefs.
Q.29 What is the shape of the atolls ?
Q.30 Distinguish between
(i) Converging and diverging tectonic plates.
(ii) Khadar and Bhangar
(iii) Western Ghats and Eastern Ghats.
B. SHORT ANSWER TYPE QUESTIONS
Q.1 “The land of India is characterised by a great diversity in its relief or physical features”. Justify the statement.
Q.2 Write four points to explain the extent , length, width and height of the Himalayas.
Q.3 How are the Himalayas divided in the eastwest direction ?
Q.4 What is the ‘bhabar’ explain.
Q.5 Write any four major characteristics of the northern plains of India.
Q.6 Write any four characteristics of Ganga -Bhamputra delta.
Q.7 Mention some features of the Ganga Basin.
Q.8 Explain how the Himalayas act as a boon for India.
Q.9 Distinguish between delta and an estuary.
Q.10 Mention any four features of the Peninsular plateau.
Q.11 What is Purvanchal ?
Q.12 Write brief facts about lakshdweep Island.
Q.13 Write any three features of Karakoram mountains range.
Q.14 Differentiate between western Himalayas eastern Himalayas.
Q.15 Give a brief description of the Indian Desert.
Q.16 What is the difference between a gorge and a rift valley ?
Q.17 What is the difference between a tributary and a distributary ?
Q.18 How are coral reefs formed ? Name two examples of coral reefs.
C. LONG ANSWER TYPE QUESTIONS
Q.1 Name the major divisions of the Himalayas from north to south.
Q.2 Give an account of the northern Plains.
Q.3 Give an account of the Island groups of India.
Q.4 Contrast the relief of the Himalayan region with that of the Peninsular Plateau.
Q.5 Name the four physical divisions of India and explain any one.
Q.6 Give a brief account of the great plains of North India.
Q.7 What are the uses of the Himalayas ? Explain.
Q.8 Compare the main features of the western coastal plain and eastern coastal plain
Q.9 Describe how the Himalayas were formed.
D. MULTIPLE CHOICE QUESTIONS
Q.1 Guru Shikhar is the highest peak of the -
(A) Aravallis
(B) Vindhyas
(C) Satpuras
(D) Western Himalayas
Q.2 A narrow opening is a mountain range which provides passage through the mountain is -
(A) Strait
(B) Valley
(C) Pass
(D) None of these
Q.3 Shipkila, Bhor, Nathula and Pal are -
(A) Peaks
(B) Passes
(C) Ranges
(D) All the above
Q.4 K2 is the highest peak of the -
(A) The Karakoram
(B) Vindhyan
(C) Satpura
(D) Western Himalayas
Q.5 Name the second highest mountain peak of the world ?
(A) K2
(B) Guru Shikhar
(C) Mt. Everest
(D) None of these
Q.6 Where is Mt. Everest situated ?
(A) India
(B) Nepal
(C) China
(D) Pakistan
Q.7 Where are the Ganga entre the northern plains ?
(A) Delhi
(B) Mumbai
(C) Haridwar (D) Allahabad
Q.8 What is the other name of the west coast -
(A) Malabar coast (B) Coromandel coast
(C) Nilgiri (D) All the above
Q.9 Which plateau lies between the Aravali and the Vindhya range -
(A) Deccan (B) Central
(C) Malwa (D) Peninsular
Q.10 Which river flows north west between Zaskar and Ladakh ranges ?
(A) Indus (B) Ganga
(C) Yamuna (D) Narmada
Q.11 Where are Lakshdweep Islands situated -
(A) Arabian sea (B) Bay of Bengal
(C) Pacific ocean (D) Indian ocean
Q.12 What is the average height of the Greater Himalayas -
(A) 8000 m (B) 7000 m
(C) 6000 m (D) 2000 m
Q.13 Where do frequent landslides occur in the Himalayas during winter and rainy season ?
(A) Shivalik (B) Himadri
(C) Middle Himalaya (D) None of these
Q.14 Which river marks the eastern-most boundary of the Himalayas ?
(A) Ganga
(B) Brahmaputra
(C) Yamuna
(D) Godavari
Q.15 Which soil dominates the Peninsular Plateau ?
(A) Red soil (B) Alluvial soil
(C) Black soil (D) Laterite soil
Q.16 ………. is the main river of the Indian desert –
(A) Ganga (B) Indus
(C) Krishna (D) Luni
Please click on below link to download pdf file for Class 9 Social Science Physical Features of India Exam Notes.
