BASIC CONCEPT OF LANDFORMS: FORMATION, TYPES AND FEATURES [ NCERT ]

BASIC CONCEPT OF LANDFORMS

The earth’s surface is highly uneven and displays an infinite variety of landforms, ranging from rugged mountains to flat plains. These variations arise due to the interaction of two fundamental processes acting continuously on the lithosphere.

Formation of Landforms: Processes

Landforms are shaped by:

• Internal Processes (Endogenic Forces)
  These originate within the earth and lead to upliftment and sinking of the earth’s crust. The surface on which we stand is in constant slow movement, resulting in large-scale structural changes.
• External Processes (Exogenic Forces)
  These act on the surface and involve wearing down (erosion) and rebuilding (deposition). Major agents include running water, wind, and ice, which continuously reshape the landscape.

Result: Formation of three major landform groups → Mountains, Plateaus, and Plains

MOUNTAINS

Mountains are elevated landforms with steep slopes and high relief. A steep hill with an elevation of more than 600 metres is generally termed a mountain.A special geographical fact highlights that Mauna Kea (10,205 m) is taller than Mount Everest when measured from its base on the ocean floor.

Types of Mountains

(A) Fold Mountains

Formed due to folding of the earth’s crust. These are high, rugged, and conical.

• Examples: Himalayas, Alps

Old Fold Mountains:

• Aravali Range (India) – highly eroded
• Appalachians (North America)
• Ural Mountains (Russia) – rounded and low

(B) Block Mountains

Formed due to faulting (breaking and displacement) of the crust.

• Uplifted blocks: Horsts
• Lowered blocks: Grabens
• Examples: Rhine Valley, Vosges Mountains

(C) Volcanic Mountains

Formed due to volcanic activity.

• Examples: Mount Kilimanjaro, Mount Fuji

Young vs Old Mountains

• Young Mountains (e.g., Himalayas):
  Characterised by tall, sharp peaks, rugged structure, and are geologically recent. They are still rising due to ongoing tectonic activity.
• Old Mountains (e.g., Aravalli Range):
  Lower and rounded, shaped by long-term erosion and denudation.

Important Mountain Peaks (Global Context)

The Himalayas

The Himalayan Range forms a massive natural barrier in the north, extending across India, Nepal, Bhutan, China, Pakistan, and Afghanistan. Many peaks exceed 8000 metres (‘Eight Thousanders’), including Mount Everest.

• Known as the “Water Tower of Asia”, feeding major rivers like Ganga, Indus, Brahmaputra
• Formed due to collision of Indian and Eurasian plates (~50 million years ago)
• Still undergoing upliftment, hence classified as young fold mountains

Meaning:

Himalaya = Hima (snow) + Alaya (abode) → “Abode of Snow”

Divisions of Himalayas

Bhagirathi River originates from Gaumukh (Gangotri Glacier).

DESERT LANDSCAPES

Cold Desert – Ladakh

A cold desert with temperatures below –30°C, low rainfall, and rugged terrain. Known as “Moonland”.

• Formed from folded oceanic sediments during Himalayan formation
• Shaped by wind erosion
• Wildlife: snow leopard, ibex, Tibetan antelope
• Important lake: Pangong Tso (salty)
• Cultural features: monasteries, festivals (Losar, Hemis)

Thar Desert (Great Indian Desert)

Located in Rajasthan, Gujarat, Punjab, Haryana, characterised by sand dunes (up to 150 m) and arid climate.

• Extreme temperatures and water scarcity
• Adaptation includes taanka/kunds, water reuse, and minimal usage practices

ARAVALLI HILLS

Among the oldest mountains (~2.5 billion years) with heights 300–900 m, and Mount Abu (>1700 m) as the highest peak.

• Acts as a barrier preventing desert expansion eastward
• Rich in minerals (marble, granite, zinc, copper)
• Associated with historical forts like Chittorgarh, Kumbhalgarh, Ranthambore

PLATEAUS

A plateau is an elevated flat land or tableland with steep sides, varying from a few hundred to several thousand metres.

Examples

• Tibetan Plateau:
  Highest plateau (4000–6000 m), known as “Roof of the World”
• Deccan Plateau:
  One of the oldest plateaus, formed by volcanic activity

Importance of Plateaus

• Rich in mineral deposits → major mining regions
• Example: Chhotanagpur Plateau → iron, coal, manganese
• Waterfallsare common:
  • Hundru Falls (Subarnarekha)
  • Jog Falls (Karnataka)
• Lava plateaus produce fertile black soil

PLAINS

Plains are large flat areas, generally below 200 metres elevation. They are fertile and densely populated, forming the backbone of human settlements and agriculture.

PENINSULAR PLATEAU

A triangular plateau surrounded by seas on three sides, representing one of the oldest landforms.

• Western Ghats: Higher and continuous
• Eastern Ghats: Lower and discontinuous

INDIAN ISLANDS

Lakshadweep

• 36 coral islands in the Arabian Sea
• Important for marine ecology and resources

Andaman & Nicobar Islands

• Over 500 islands, volcanic origin
• Strategic “outposts of India”
• Historical importance: Cellular Jail
• Unique feature: Barren Island (only active volcano in India)

NORTHEASTERN HILLS

Includes Garo, Khasi, Jaintia Hills (Meghalaya Plateau).

• Heavy rainfall, lush greenery
• Known for waterfalls, living root bridges, and eco-friendly villages (Mawlynnong)

MOUNTAIN ENVIRONMENT

Mountain regions support montane forests dominated by coniferous trees such as pine, fir, spruce, deodar.

Altitudinal Variation

• Lower slopes: Dense forests
• Higher altitudes: Grasses, mosses, lichens

Fauna

Includes snow leopard, yak, ibex, Himalayan tahr, black bear, golden eagle

CULTURAL SIGNIFICANCE OF MOUNTAINS

Mountains are regarded as sacred landscapes.

• Mount Everest:
  • Tibetan: Chomolungma (Mother Goddess of the World)
  • Nepali: Sagarmatha (Goddess of the Sky)
• Mount Kailash: Sacred to Hinduism, Buddhism, Jainism, Bon

Literary Reference:

Kalidasa described the Himalaya as “Lord of Mountains”

NOTABLE PERSONALITIES

• Bachendri Pal – First Indian woman to climb Everest (1984)
• Arunima Sinha – First female amputee to climb Everest (2013)

ANCIENT INDIAN LANDSCAPE CLASSIFICATION (SANGAM)

FINAL REVISION LINES

• Mountains → Young (Himalayas) vs Old (Aravalli)
• Plateaus → Mineral-rich elevated flat lands
• Plains → Fertile and densely populated
• Rivers → Cultural and economic backbone
• Human adaptability → Present across all landforms