India - Physiography Chapter Notes - Class 8 PDF Download

Introduction

Physiography

• India’s geological past traces back to Gondwanaland, an ancient landmass.
• About 50 million years ago, it separated and collided with the Tibetan landmass.
• This collision formed the Himalayas, known as young fold mountains.
• India ranks as the seventh largest country globally by area.

Location and Extent of India

• India is fully located in the Northern and Eastern Hemispheres.
• Mainland India spans latitudes 8°4’N to 37°6’N and longitudes 68°7’E to 97°25’E.
• Indira Point, the southernmost tip, lies at 6°45’N in the Andaman and Nicobar Islands.
• The Tropic of Cancer (23°30’N) splits India into nearly two equal parts.
• Both east-west and north-south extents are around 3,000 kilometers.
• A two-hour time lag exists between the eastern and western ends due to longitudinal stretch.
• India’s standard time follows the 82°30’E longitude, called the Standard Meridian, passing through Prayagraj, Uttar Pradesh.
• Latitudinal extent affects day and night duration across the country.

Implications of Latitudinal Extensions

• The Tropic of Cancer divides India into two zones.
• The southern half, in the tropical zone, has warm, tropical climate with no distinct winter.
• The northern half, in the subtropical zone, experiences hot summers and cold winters.
• Temperature decreases as latitude increases, varying from warm Kerala to cold Kashmir.
• Day and night duration differs greatly: Kanyakumari has nearly equal day and night.
• Kashmir, far from the equator, sees a difference of almost 5 hours.
• Regions farther from the equator get uneven sunlight, affecting day-night lengths.

Boundaries of India

• Afghanistan and Pakistan border India to the northwest.
• China, Bhutan, and Nepal are northeastern neighbors.
• The Chinese border runs from Jammu and Kashmir to Arunachal Pradesh, touching Himachal Pradesh, Uttarakhand, and Sikkim.
• Bangladesh lies to the east, and Myanmar to the far east.
• Sri Lanka is separated by the Palk Strait and Gulf of Mannar.
• Maldives, an island neighbor, lies to the southwest.
• The Himalayas bound India on the northern and northeastern sides.

Political Divisions

• India, a vast nation, has 28 states and 9 union territories.
• States and territories are grouped into zones based on location.

Zones and States/Union Territories

• Northwestern India: Chandigarh, Haryana, Himachal Pradesh, Jammu and Kashmir, Ladakh, Punjab
• Northern India: Delhi, Uttar Pradesh, Uttarakhand
• Western India: Dadra and Nagar Haveli, Daman and Diu, Gujarat, Maharashtra, Rajasthan
• Central India: Madhya Pradesh, Chhattisgarh
• Eastern India: Bihar, Jharkhand, Odisha, Sikkim, West Bengal
• Northeastern India: Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland, Tripura
• Southern India: Andhra Pradesh, Goa, Karnataka, Kerala, Puducherry, Tamil Nadu

State and Capitals

Union Territories and Capitals

Physiographic Features of India

• India boasts diverse physical features, from lofty mountains to flat plains.
• Six main divisions exist based on physical characteristics.
• Divisions: Northern Mountains, Northern Plains, Peninsular Plateau, Great Indian Desert, Coastal Plains, Islands

Northern Mountains

• The Himalayas, the highest range, mean "abode of snow" in Sanskrit.
• They span 2,500 kilometers from the Pamir Knot to Purvanchal.
• Width varies: 400 kilometers in the west, narrowing to 150 kilometers in the east.
• Formed of sedimentary rocks, they are young fold mountains.
• Three parallel ranges: Himadri, Himachal, and Sivalik.

Greater Himalayas or Himadri

• Northernmost range with an average height of 6,000 meters.
• Width ranges from 120 to 190 kilometers.
• A continuous range with peaks over 8,000 meters: Mt Everest (Nepal), Kanchenjunga, Makalu, Dhaulagiri, Nanga Parbat.
• Peaks are mostly on borders and perennially snow-covered.
• High passes include Rohtang, Bara-lacha La, Shipki La, and Zoji La.

Lesser Himalayas or Himachal

• Lies south of Himadri, with altitudes of 1,000 to 4,500 meters.
• Average width is 50 kilometers.
• Includes ranges like Pir Panjal, Dhaula Dhar, and Mahabharata.
• Popular hill stations: Manali, Kullu, Dalhousie, Mussoorie, Shimla, Nainital, Darjeeling.
• These are easily accessible and attract tourists.

Outer Himalayas or the Sivaliks

• Outermost range with altitudes of 900 to 1,100 meters.
• Width varies from 10 to 50 kilometers.
• Hills are narrow, discontinuous, and merge with other ranges.
• Valleys between Sivaliks and Himachal are called Duns, e.g., Dehradun, Kotlidun, Patlidun.
• Terai, a densely forested and marshy region, lies at the foothills.

The Purvanchal Range

• Located along the India-Myanmar border in the east.
• Average altitude is below 3,000 meters.
• Northern part: Patkai Bum, Naga Hills.
• Southern part: Lushai Hills, Mizo Hills.
• In Meghalaya: Garo Hills, Khasi Hills, Jaintia Hills.

The Karakoram Range

• Found north of the Himalayas in Kashmir.
• Lies on the border of India, Pakistan, China, and extends to Afghanistan and Tajikistan.
• Has peaks over 8,000 meters, mostly outside India.

The importance of the Himalayas to India is listed below:

• Shields India from cold northeastern trade winds from Tibet.
• Guides monsoon winds for rainfall.
• Rich in resources and biodiversity.
• A major tourist attraction.
• Source of key rivers.

Northern Plains

• Also called Gangetic Plains, located south of the Himalayas and north of the Peninsular Plateau.
• Formed by alluvial deposits from the Indus, Ganga, and Brahmaputra rivers.
• Spans 2,400 kilometers and is densely populated.
• Very fertile, supporting crops like wheat, rice, sugarcane, pulses, oilseeds, and jute.
• Divided into Western Plain and Ganga-Brahmaputra Plain.
• Western Plain
  • Formed by the Indus and tributaries: Jhelum, Chenab, Ravi, Beas, Sutlej.
  • Jhelum and Chenab flow through Jammu and Kashmir.
  • Ravi, Beas, and Sutlej cross the Punjab-Haryana plains.
  • Much of this plain lies in Pakistan.
  • Doabs, land between converging rivers, are found in Punjab.
• Ganga-Brahmaputra Plain
  • Formed by sediments from the Ganga and Brahmaputra rivers.
  • The Ganga’s key tributary is the Yamuna, both originating in the Himalayas.
  • The Brahmaputra, called Tsangpo in Tibet, flows east, then south and west through Assam.
  • Ganga Plain stretches between Ghaggar and Teesta rivers.
  • Brahmaputra Plain forms the eastern part.
  • Both rivers meet as the Padma in Bangladesh, creating the world’s largest delta.

The importance of the Northern Plains is listed below:

• Fertile soil and water resources make it ideal for agriculture, known as India’s granaries.
• Flat land, slow rivers, and good climate boost economic and social growth.
• Strong road and rail networks support large-scale industrialization.

Peninsular Plateau

• Largest and oldest hard rock formation, triangular in shape.
• Part of ancient Gondwanaland.
• Divided into Central Highlands and Deccan Plateau.

Central Highlands

• Stretches from the Narmada River to the Northern Plains.
• Bounded by Aravallis in the west and Satpura range in the south.
• Eastern part includes Rajmahal hills.
• Includes Malwa and Chhota Nagpur Plateaus.
• Rivers: Betwa, Chambal, Ken flow through Malwa.
• Hills: Mahadeo, Kaimur, Maikal in Chhota Nagpur.

Deccan Plateau

• Separated from Chhota Nagpur by a geological fault.
• Deccan Trap, a black soil area, formed by volcanic eruptions, suits cotton and sugarcane.
• Divided into Western Ghats and Eastern Ghats.
• Western Ghats
  • A mountain range along the western coast, also called Sahyadri.
  • Continuous, crossed only via passes like Thal Ghat, Bhor Ghat, and Pal Ghat.
  • Highest peak: Anamudi (2,695 meters).
  • Famous waterfalls: Jog Falls (Sharavati River), Shivasamudram Falls (Kaveri River).
• Eastern Ghats
  • Discontinuous, low mountain ranges along the eastern coast.
  • Run from south of Mahanadi Valley to Nilgiri Hills.
  • Highest peak: Mahendragiri (1,501 meters).
  • Drained by Mahanadi, Godavari, Krishna, and Kaveri rivers.
  • Nilgiri Hills link Western and Eastern Ghats in the south.

The Great Indian Desert

• Also known as the Thar Desert, lies northwest of Aravalli Hills.
• Receives less than 150 millimeters of rain yearly, making it dry.
• A region of inland drainage with Luni as the main river.
• Other streams appear during the rainy season.
• Contains salt lakes, with Sambhar Lake being the largest.
• Features crescent-shaped dunes called barchans.

Coastal Plains

• Run parallel to the Arabian Sea and Bay of Bengal.
• Divided into Western and Eastern Coastal Plains.
• Western Coastal Plain
  • Extends from Rann of Kutch (Gujarat) to Kanyakumari (Tamil Nadu).
  • Divisions: Kutch and Kathiawar Coast (Gujarat), Konkan Coast (Maharashtra), Goan Coast (Goa and Karnataka), Malabar Coast (Kerala).
  • Narrow in the middle, wider in the north and south.
  • Rivers here do not form deltas.
• Eastern Coastal Plain
  • Runs along the Bay of Bengal, broader than the western coast.
  • An emergent plain with fewer ports and harbors.
  • Has well-developed deltas from Mahanadi, Godavari, Krishna, and Kaveri rivers.

Islands

• Andaman and Nicobar Islands
  • Located in the Bay of Bengal, with 204 islands.
  • Main groups: Ritchie’s Archipelago, Labyrinth Islands.
  • Barren Island hosts Barren Volcano, an active volcano.
  • Ten Degree Channel separates Andaman and Nicobar Islands.
• Lakshadweep Islands
  • Found in the Arabian Sea, near the Malabar Coast of Kerala.
  • Consist of 43 coral-formed islands.
  • Rich in diverse flora and fauna.
  • Minicoy is the largest island.