Ques 1: Describe the important features of the Peninsular Plateau.
Ans: The Peninsular Plateau of India lies to the south of the Northern Plains and extends up to the tip of the Indian peninsula. The Peninsular Plateau is a tableland with gently rising rounded hills and broad, shallow valleys.
Fig: Peninsular plateau It is roughly triangular in shape. It is the oldest and the most stable landmass of India. The plateau is formed of old crystalline igneous and metamorphic rocks.
The Peninsular Plateau consists of two broad divisions – the Central Highlands and the Deccan Plateau. The part of the Peninsular plateau lying to the north of the Narmada river is known as Central Highlands.
It comprises of Malwa Plateau, Bundelkhand and Baghelkhand plateaus, the Vindhya Range and extends as Chhota Nagpur Plateau. The Aravalis are highly denuded old hills that lie on the western and northwestern margins of the Peninsular Plateau. The part of the Peninsular Plateau lying to the south of river Narmada is known as Deccan Plateau.
It is a triangular landmass with broad base in the north and tapers southward. It is formed due to lava flows, so a greater part of it is composed of basaltic rocks of volcanic origin.
It is flanked by the Satpura range in the north. The Mahadev, the Kaimur hills and Maikal range form its eastern extensions. The Deccan Plateau is flanked by the Western Ghats in the west and Eastern Ghats in the east.
The Western Ghats have comparatively higher elevation of average 900 to 1600 metres. The Eastern Ghats have an average elevation of 600 metres. So the plateau is higher in the west and slopes gently eastwards. The black soil area of the Deccan Plateau is known as Deccan Trap.
Ques 2: Write a note on the different parts of the Great Himalayan range.
Ans: The Himalayas are the one of the loftiest and most rugged mountain systems of the world. The mountain ranges of the Himalayas run in a west-east direction from the Indus to the Brahmaputra, stretching along the entire northern boundary of India. Geologically they are young and structurally fold mountain system.
Fig: The great Himalayan rangeThe Himalayas consists of three sections comprising parallel ranges running from west to east. The nothern-most section is known as the Greater or Inner Himalayas. On account of its permanent snow cover and glaciers the section is also termed as Himadri.
It is the most continuous section. The average height of these ranges is 6000 metres. All the prominent and loftiest peaks of the Himalayas are located here. Some of prominent peaks are the Everest (8848 m) in Nepal, Kanchenjunga (8598 m in Sikkim), Nanga Parbat (in Kashmir), Nanda Devi (Uttarakhand) and Namcha Barwa (in Tibet, near Arunachal Pradesh) and Dhaulagiri and Annapurna in Nepal.
To the south of Himadri lie the rugged ranges of the Lesser Himalayas or the Himachal. Their average width is 50 km. The average height ranges between 3700 and 4500 metres. The Pir Panjal range, the Dhaula Dhar and Mahabharat ranges are important ranges.
The famous valley of Kashmir, the Kangra and the Kullu Valleys in Himachal are located in this range. The outermost range of the Himalayas is called the Outer Himalayas or the Shivaliks. They extend over a width of 10-50 km. They are discontinuous ranges. Their average height is between 900 and 1100 metres.
They are composed of unconsolidated sediments, gravel and alluvium brought down by the rivers that rise in the northern ranges. Hence, they are the youngest section of the Himalayas.Longitudinal valleys known as duns lie between the Lesser Himalayas and Shivaliks, e.g., Dehra Dun, Kotli Dun, Patli Dun.
Ques 3: Describe the formation of India from Gondwanaland.
Ans: According to the ‘Theory of Plate Tectonics’ presented by earth scientists, the earth’s crust is composed of tectonic plates. The movement of these plates have influenced the evolution of present landforms of India.
Fig: Tectonic PlateThe southern part of the ancient super-continent Pangaea is known as Gondwanaland. It included India, Australia, South Africa and South America as one single landmass. Geologically, the Peninsular Plateau, which is one of the oldest landmasses of the earth’s surface, was part of the Gondwanaland.
Tectonic forces split the crust into a number of plates. A part of the Gondwanaland, the Indo- Australian plate, drifted northwards. This resulted in the collision of this plate with the much larger Eurasian plate.
The intervening portion between Angaraland in the north and Gondwanaland in the south was occupied by Tethys Sea. Due to this collision, the sediments that had accumulated in the Tethys geosyncline was uplifted and folded. This resulted in the formation of the lofty Himalayas.
The Himalayan upliftment out of the sediments of the Tethtys Sea and subsidence of the northern flank of the Peninsular Plateau resulted in the formation of a large basin.
Over millions of years the depression gradually got filled with deposition of sediments by the rivers flowing from the mountains in the north and the Peninsular Plateau in the south.
The interplay of three major river systems – the Indus, the Ganga, the Brahmaputra and their tributaries formed a fertile, flat land of extensive alluvial deposits known as the Northern Plains.
Ques 4: Distinguish between the Northern Plains and the Peninsular Plateau. (Important)
Ans: The Northern Plains The Peninsular Plateau
|The Northern Plains||The Peninsular Plateau|
|1. Geologically, the Northern Plains were formed in recent geological period|
1. Geologically, the Peninsular Plateau is part of die Gondwanaland. die southern part of ancient super-continent Pangaea
|2. Northern Plains are the most recent landform|
2. The Peninsular plateau is part of oldest landmass.
|3. They are being formed and reshaped by the river systems.||3. It is one of the most stable land blocks|
|4. It is a fertile, level land||4. It a plateau or tableland with gently nsmg rounded hills and wide shallow valleys.|
|5. The Northern Plains are formed of alluvial deposits brought down by the rivers.||5. The Peninsular Plateau is composed of old crystalline igneous and metatrophic rocks.|
|6. The Northern Plains are divided into three sections : (i) The Punjab Plains formed by Indus and its tributaries, (ii) The Ganga Plains in North India|
(iii) The Brahmaputra Plains Assam
|6. The Peninsular Plateau is divided mainly into two broad divisions : (i) the Central Highlands and (ii) the Deccan Plateau|
|7. The Northern Plains are covered with rich, fertile alluvial soil ideal for high agricultural production||7. A distinct feature of the Peninsular Plateau is the black soil area known as Deccan Trap. This soil is ideal for growth of cotton.|
|8. It is the most densely populated region of India on account of fertile soil, adequate water and favourable climate||8. It has moderate density of population.|
Ques 5: Which part of the Himalayas is known as Purvanchal? Write a short note on the Purvanchal Himalayas. (Important)
Ans: The eastern hills and mountains of the Himalayas running along the eastern boundary of India are known as Purvanchal.
Fig: Division of HimalayasThey are located in the northeastern states of India. The river Brahmaputra marks the easternmost boundary of the Himalayas. Beyond the Dibang gorge, the Himalayas bend sharply to the south and spread along India’s eastern border.
They are known as Purvanchal. They run mostly as parallel ranges with valleys in between. They are mostly composed of strong sandstone, a sedimentary rock. The Purvanchal are less spectacular than the Himalayas and are of medium height. The hills and ranges are covered with dense forests.
Some important hills of the Purvanchal are :
(i) the Patkai Bum and Naga hills
(ii) the Mizo hills and Manipur hills
(iii) the Garo, Khasi and Jaintia hills along Meghalaya-Bangladesh border.
(iv) the Dafla hills in the north.