Brief Summary
This live session by Digraj Singh Rajput covers the chapter "Physical Features of India" for class 9, focusing on the major physiographic divisions: the Himalayan Mountains, Northern Plains, Peninsular Plateau, Indian Desert, Coastal Plains, and Islands. The session includes explanations of the formation, characteristics, and significance of each feature, along with interactive polls and map visualizations. The Himalayas are divided into ranges and sections, the Northern Plains into regions based on physiographic structure, and the Peninsular Plateau into central highlands and the Deccan Plateau. The session also touches upon the importance of these features for the country's geography, economy, and civilization.
- The Himalayas are young fold mountains divided into Himadri, Himachal, and Shivalik ranges.
- The Northern Plains are formed by the depositional work of rivers and divided into Bhabar, Terai, Khadar, and Bhangar regions.
- The Peninsular Plateau, the oldest landmass, is divided into the Central Highlands and the Deccan Plateau.
- The Indian Desert lies west of the Aravalli Hills and features sandy plains and barchans.
- Coastal Plains are divided into Western and Eastern Coastal Plains, with distinct characteristics.
- India has two island groups: Lakshadweep (coral islands) and Andaman and Nicobar Islands (elevated portions of submarine mountains).
Introduction and Welcome
The session begins with a warm welcome to the audience, celebrating the channel's milestone of reaching 100,000 subscribers on "The Social Brains." The host expresses gratitude and excitement for the live class on "Physical Features of India," emphasizing its engaging nature and the opportunity to virtually travel across India. The class aims to complete the chapter in under an hour, focusing on important questions and revisions.
Major Physical Features of India
The chapter discusses India's major physical features, including the Himalayan Mountains, Northern Plains, Peninsular Plateau, Indian Desert, Coastal Plains, and Islands. These physiographic divisions shape India's landscape and play a crucial role geographically and strategically. The session will cover the formation and characteristics of each feature in detail.
The Himalayan Mountain System
The Himalayan mountain range, stretching 2400 km long, consists of three parallel ranges: Himadri, Himachal, and Shivalik. Formed by the collision of the Eurasian and Indo-Australian plates, these young fold mountains vary in width from 400 km in Kashmir to 150 km in Arunachal Pradesh. Himadri, also known as the Greater or Inner Himalayas, is the northernmost continuous range with lofty peaks and an average height of 6000 meters, perpetually covered in snow. Himachal, the middle range, features longitudinal valleys and hill stations, with altitudes ranging from 3700 to 4500 meters and an average width of 50 km. Shivalik, the outermost range, is composed of unconsolidated sediments and is easily passable, with valleys called "duns" like Dehradun.
Divisions of the Himalayas
The Himalayas can be divided into four sections: Punjab Himalayas (between Indus and Sutlej rivers), Kumaon Himalayas (between Sutlej and Kali rivers), Nepal Himalayas (between Kali and Teesta rivers), and Assam Himalayas (between Teesta and Brahmaputra/Dawang rivers). Beyond the Dihang gorge, the Himalayas bend southward, forming Purvanchal, also known as the Eastern Hills and Mountains, comprising the Patkai Hills, Naga Hills, Manipur Hills, and Mizo Hills.
The Northern Plains
The Northern Plains, located south of the Himalayas, cover an area of 7 lakh square kilometers. Formed by the depositional work of rivers originating from the Himalayas, these plains are 2400 km in length and 240 to 320 km in breadth. The rivers bring eroded material from the mountains, depositing it to form a flat plain area. The Northern Plains are characterized by features like Khadar (fertile region with fine particles), Bhangar (region with larger depositional features), meanders, oxbow lakes, distributors, and deltas. The land between two rivers is called "doab," exemplified by the Ganga-Yamuna doab and the Punjab region formed by five rivers: Jhelum, Chenab, Ravi, Vyas, and Sutlej.
Regions of the Northern Plains
The Northern Plains are divided into four regions based on relief features: Bhabar (adjacent to the Himalayas, characterized by big boulders and disappearing streams), Terai (wet marshy region where streams reappear), Khadar (fertile region close to the river bed, renewed annually by floods), and Bhangar (older alluvium, away from the river bed). Riven islands, formed by depositional work in the river bed, are also a feature of the Northern Plains. The North Plain can also be divided into three sections: the Punjab Plain, the Ganga Plain, and the Brahmaputra Plain.
The Peninsular Plateau
The Peninsular Plateau is a tableland surrounded by water on three sides, making it a peninsula. It is the oldest landmass, part of the Gondwana Land, and is divided into two divisions: the Central Highlands and the Deccan Plateau. The Central Highlands, north of the Narmada River, cover a major area of the Malwa Plateau and extend eastward to Bundelkhand, Baghelkhand, and the Chota Nagpur Plateau. The Deccan Plateau is a triangular landmass south of the Narmada River, flanked by the Western Ghats and Eastern Ghats.
Western Ghats and Eastern Ghats
The Western Ghats and Eastern Ghats mark the western and eastern edges of the Deccan Plateau, respectively. The Western Ghats, parallel to the western coast, are continuous and can be crossed only through passes, with the highest peak being Anaimudi (2695 meters). The Western Ghats cause orographic rainfall due to air masses from the Arabian Sea. The Eastern Ghats, discontinuous and irregular, are dissected by rivers draining into the Bay of Bengal, with the highest peak being Mahendragiri (1501 meters).
The Indian Desert
The Indian Desert, also known as the Thar Desert, lies towards the western margin of the Aravalli Hills. It is a sandy plain covered with sand dunes, receiving low rainfall (below 150 mm per year). The region is characterized by barchans (crescent-shaped sand dunes) and the Luni River, the only major river in this region.
The Coastal Plains
The Coastal Plains are divided into the Western Coastal Plain and the Eastern Coastal Plain. The Western Coastal Plain, between the Western Ghats and the Arabian Sea, is divided into the Konkan Coast (Mumbai-Goa), Kannada Coast (central Karnataka), and Malabar Coast (Kerala). The Eastern Coastal Plain, between the Eastern Ghats and the Bay of Bengal, is broader due to the formation of deltas by rivers and is divided into the Northern Circar (Orissa-West Bengal) and the Coromandel Coast (Tamil Nadu-Andhra Pradesh).
The Island Groups
India has two island groups: Lakshadweep and Andaman and Nicobar Islands. Lakshadweep, close to the Malabar Coast of Kerala, is composed of coral islands, including Laccadive, Minicoy, and Amindivi, covering a small area of 32 square kilometers. Kavaratti is the administrative headquarters of Lakshadweep. Andaman and Nicobar Islands, located in the Bay of Bengal, are believed to be elevated portions of submarine mountains, experiencing an equatorial climate and thick forest cover. The islands are divided into Andaman Islands in the north and Nicobar Islands in the south.
Importance of Diversity in Physical Features
The diversity in physical features offers several advantages. The Northern Mountains are a source of water and forest wealth. The Northern Plains act as granaries for agriculture. The Plateau region is a storehouse of minerals, crucial for industrialization. The Coastal Plains and Islands provide opportunities for fishing and port activities. Each feature contributes to the country's geography, economy, and civilization.
