Choose the right answer from the four alternatives given below.
(i) A landmass bounded by sea on three sides is referred to as
(d) none of the above
(ii) Mountain ranges in the eastern part of India forming its boundary with Myanmar are collectively called as
(d) none of the above
(iii) The western coastal strip, south of Goa is referred to as
(d) Northern Circar
(iv) The highest peak in the Eastern Ghats is
(a) Anai Mudi
2 Answer the following questions briefly.
(i) What are tectonic plates?
Ans. Tectonic plates is a term emerged from “Theory of Plate Tectonics”. According to this theory, the crust (upper part) of the earth is divided in seven major and some minor plates. When these plates move, stress builds up within plates which leads to folding, faulting and volcanic activity.
(ii) Which continents of today were part of the Gondwana land?
Ans. The Gondwanaland included India, Australia, South Africa and South America as one single land mass.
(iii) What is the bhabar?
Ans. Bhabar is one of the four regions of the northern plains. When the rivers after descending from the mountains deposit pebbles in a narrow belt of about 8 to 16 km in width. This pebble belt lies parallel to the slopes of the Shiwaliks and all the stream disappear. This pebble belt is known as bhabar.
(iv) Name the three major divisions of the Himalayas from north to south.
Ans. The Himalayas start from Jammu and Kashmir and stretches till Arunachal Pradesh. It forms an arc, which covers a distance of about 2,400 Km. Its width varies from 400 Km in Kashmir to 150 Km in Arunachal Pradesh. The Himalaya consists of three parallel ranges in its longitudinal extent :-
- The northern most range is known as the Great or Inner Himalayas or the Himadri
- To the south of Himadri Rugged mountain system Himachal or lesser Himalaya
- The outer most range of the Himalayas is called the Shiwaliks
(v) Which plateau lies between the Aravali and the Vindhyan ranges?
Ans. Malwa Plateau.
(vi) Name the island group of India having coral origin.
Ans. Lakshadweep Islands lying close to the Malabar coast of Kerala has group of islands which is composed of small corals.
3. Distinguish between
(i) Converging and diverging tectonic plates
Ans. Converging tectonic plates :- The crust (upper part) of the earth is divided in seven major and some minor plates. When these plates moves closer to each other, they for convergent boundary. Converging means coming closer.
Diverging tectonic plates:- When the same plates move away from each other, they form divergent boundary. Diverging means moving away or drawing apart.
(ii) Bhangar and Khadar
Ans. Alluvium soil deposit is formed due to continuous running of water. Alluvium deposit is of two types :- Bhangar and Khadar.
Bhangar is the older deposit of alluvium. They lie above the flood plains of the rivers and are present as a terrace like feature. Since they are older deposits, it contains calcareous deposits which are also called Kankar.
The newer, younger deposits of the flood plains are called Khadar. Since they are new and young, hence they get renewed almost every year. Khadar is fertile and ideal for intensive agriculture.
(iii) Western Ghats and Eastern Ghats
Ans. The Western Ghats and the Eastern Ghats mark the western and the eastern edges of the Deccan Plateau in India.
Difference Between Western Ghats and Eastern Ghats :-
1. Western Ghats receive much more rainfall than Eastern Ghats and reason is because of South Western Monsoon
2. Western Ghats has a greater diversity of flora and fauna
3. Western Ghats is higher is elevation than Eastern Ghats
4. Anai Mudi is the highest peak in Western Ghats and Mahendragiri hills is the highest peak in Eastern Ghats
5. Western Ghats have continuous chain of hills starting from Tapti valley in north to Kanyakumari in the South and Eastern Ghats are discontinuous chain of hills from Mahanadi River in north and Vaigai River in the south.
6. Most of the rivers that rise in western Ghats drain into Arabian sea and Most of the rivers that rise in Eastern Ghats drain into Bay of Bengal.
(iv) Describe how the Himalayas were formed.
Ans. When Indo-Australian plate got separated from the Gondwanaland, it started drifting towards north. The northward drift resulted in the collision of the plate with the much larger Eurasian Plate this began 50 million years ago and continues today. Due to this collision, the sedimentary rocks which were accumulated in the geosyncline known as the Tethys were folded to form the mountain system of western Asia and Himalaya.
(v) Which are the major physiographic divisions of India? Contrast the relief of the Himalayan region with that of the Peninsular plateau.
Ans. 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 are geologically young and fold mountains stretched over the northern borders of India. These mountains range from west to east direction from the Indus to the Brahmaputra. The Himalayas have the most rugged mountain barriers of the world they form in arc which covers a distance of about 2400 km and has a bit that varies from 400 km in Kashmir to 150 km in Arunachal Pradesh. The core of Himalaya is composed of granite and the upper layer is covered with snow mountains and glaciers.
Coming to the Northern plains they are formed because of three major river systems – the Indus, the Ganga, and the Brahmaputra along with their tributaries. The northern plain is formed of Alluvial soils basically it all gets collected at the foothills of the Himalayas over millions of Years by running water. The northern plain is 2400 km long and the width varies from 240 to 320km. This region is densely populated. Because of rich soil cover along with adequate water supply northern plain becomes the agriculturally favorable part of India.
(vi) Give an account of the Northern Plains of India.
Ans. The northern plain of India is formed by three river systems, i.e. the Indus, the Ganga and the Brahmaputra; along with their tributaries. This plain is composed of alluvial soil which has been deposited over millions of years. The total area of the northern plain is about 7 lakh square kilometer. It is about 2400 km long. Width is about 240 to 320 km. Northern plains are most densely populated areas of the country. Here, we find alluvial soil, thus making the plain very fertile and agriculturally very productive. This region is also densely populated and most of the people indulge in agricultural activities.
The northern plain is divided into three sections, i.e. the Punjab Plain, the Ganga Plain and the Brahmaputra Plain.
1. Punjab Plains: The Punjab plains form the western part of the northern plain. This is formed by the Indus and its tributaries; like Jhelum, Chenab, Ravi, Beas and Sutlej. A major portion of this plains is in Pakistan. Doabs are found in Punjab plains.
2. Ganga Plains: This plain extends between Ghaggar and Tista rivers. The northern states, Haryana, Delhi, UP, Bihar, part of Jharkhand and West Bengal in the east lie in the Ganga plains.
3. Brahmaputra Plains: This plain forms the eastern part of the northern plain and lies in Assam.
Based on the relief features; the northern plain can be divided into four regions, they are:- Bhabar, Terai, Bhangar and Khadar.
1.Bhabar: After descending from the mountains, the rivers deposit pebbles in a narrow belt. The width of this belt is about 8 to 16 kms. It lies parallel to the Shiwaliks. Bhabhar is the gently-sloping coarse alluvial zone below the Siwalik Hills (outermost foothills of Himalayas) where streams disappear into permeable sediments. The underground water level is deep in this region.
2. Terai: The terai region lies towards south of the bhabar belt. In this region, the streams reappear and make a wet, swampy and marshy region. This region was full of forest and wildlife but after partition all this area was cleared and was converted into agricultural land for the settlement of the migrants.
3. Bhangar: Bhangar is the largest part of the northern plain and is composed of the oldest alluvial soil. They lie above the flood plains. They resemble terraces. The soil of this region is locally known as kankar and is composed of calcareous deposits.
4. Khadar: The floodplains formed by younger alluvium are called Khadar. The soil in this region is renewed every year and is highly fertile. This region is very suitable for intensive agricultural activities.
(vii) Write short notes on the following.
(i) The Indian Desert
The Indian desert lies towards the western margins of the Aravali Hills. This region gets scanty rainfall which is less than 150 mm in a year. Hence they climate is arid and vegetation is scanty. Luni is the only large river but some streams appear during rainy season. Crescent-shaped dunes (barchans) abound in this area.
(ii) The Central Highlands
The Central Highlands lies to the north of the Narmada river. It covers the major portion of the Malwa plateau. The rivers in this region flow from southwest to northeast; which indicates the slope of this region. It is wider in the west and narrower in the east. Bundelkhand and Baghelkhand mark the eastward extension of this plateau. The plateau further extends eastwards into the Chhotanagpur plateau.
(iii) The Island groups of India
The Lakshadweep Islands are in the Arabian Sea. Its area is 32 sq km. The administrative headquarters of Lakshadweep is at Kavaratti island. This group of islands is rich in terms of biodiversity. The Andaman and Nicobar Islands are bigger in size and has more number of islands. This group of islands can be divided into two groups. The Andaman is in the north and the Nicobar is in the south. These islands too have rich biodiversity.