Fundamentals of Physical Geography

Landforms and Their Evolution Notes

Class 11 Geography Chapter 6 – Landforms and Their Evolution Notes

These Landforms and Their Evolution Class 11 Notes explain how different geomorphic agents like running water, groundwater, glaciers, waves and wind shape the Earth’s surface through erosion and deposition. The chapter discusses erosional and depositional landforms along with stages of landscape evolution. (NCERT Pages 47–62)

These notes are highly useful for UPSC, SSC, Railways, State PSC, CUET, CBSE Board Exams and other competitive examinations because geomorphology, landforms and geomorphic processes are frequently asked in Geography and Environment sections. Exact NCERT page references are included throughout the notes for revision and exam preparation. (NCERT Pages 47–62)

Table of Contents

Chapter Overview

This chapter explains the formation and evolution of landforms through geomorphic processes. It discusses the role of running water, groundwater, glaciers, waves and wind in shaping the Earth’s surface. The chapter also explains various erosional and depositional landforms formed by these agents. (NCERT Pages 47–62)

Major Topics Covered

  • Meaning of landforms
  • Landscape evolution
  • Running water landforms
  • Erosional and depositional landforms
  • Groundwater and karst topography
  • Glacial landforms
  • Coastal landforms
  • Wind erosion and deposition
  • Desert landforms
  • Sand dunes

Meaning of Landforms and Landscape Evolution (NCERT Page 47)

Landforms

  • Small to medium tracts of Earth’s surface are called landforms.
  • Several related landforms together form a landscape.
  • Landforms are created by geomorphic processes and agents.
  • Landforms continuously change due to erosion and deposition.

Landscape Evolution

  • Landforms pass through stages:
    • Youth
    • Mature
    • Old age
  • Climatic changes and tectonic movements modify landforms.

Running Water as a Geomorphic Agent (NCERT Pages 47–48)

Running Water

  • Most important geomorphic agent in humid regions.
  • Causes:
    • Erosion
    • Transportation
    • Deposition

Components of Running Water

Component Description
Overland Flow Water flowing as sheet
Linear Flow Streams and rivers

Evolution of River Valleys (NCERT Pages 48–49)

Valley Development

  • Sheet erosion
  • Formation of rills
  • Development of gullies
  • Formation of valleys

River Landscape Stages

Stage Features
Youth V-shaped valleys, waterfalls
Mature Wider valleys, meanders
Old Floodplains, oxbow lakes

Erosional Landforms by Running Water (NCERT Pages 48–49)

Types of Valleys

Valley Type Features
V-shaped Valley Narrow and deep
Gorge Deep valley with steep sides
Canyon Deep valley with step-like sides

Potholes and Plunge Pools

  • Circular depressions formed on rocky river beds.
  • Created due to abrasion by pebbles and boulders.
  • Deep holes at waterfall bases are called plunge pools.

Incised or Entrenched Meanders

  • Deep meanders cut into hard rocks.
  • Formed due to vertical erosion.

River Terraces

  • Old floodplain or valley floor surfaces.
  • Indicate former river levels.

Depositional Landforms by Running Water (NCERT Pages 49–51)

Alluvial Fans

  • Cone-shaped deposits at foothills.
  • Formed when streams enter plains.

Deltas

  • Deposits formed where rivers meet sea.
  • Deposits are well stratified.
  • Distributaries increase with delta growth.
  • Fine sediments carried into sea.

Floodplains

  • Flat depositional surfaces beside rivers.
  • Formed by river deposition during floods.

Associated Features

Feature Description
Natural Levees Raised river banks
Point Bars Deposits along meanders
Oxbow Lakes Cut-off meander loops

Meanders (NCERT Page 51)

  • Loop-like river channel patterns.
  • Form due to lateral erosion.

Features

  • Concave bank → erosion
  • Convex bank → deposition
  • Deep meanders may form oxbow lakes.

Groundwater and Karst Topography (NCERT Pages 51–54)

Karst Topography

  • Formed mainly in limestone and dolomite regions.
  • Dominated by:
    • Solution
    • Deposition

Erosional Karst Landforms

  • Sinkholes and dolines
  • Lapies
  • Caves

Depositional Karst Landforms

Feature Description
Stalactites Hang from cave roof
Stalagmites Rise from cave floor
Pillars Form when stalactites and stalagmites join

Glaciers (NCERT Pages 54–57)

Types of Glaciers

Type Description
Continental Glacier Large ice sheet
Valley Glacier Glacier flowing in valleys

Glacial Erosional Landforms

  • Cirques
  • Horns
  • Arêtes
  • U-shaped valleys
  • Fjords

Glacial Depositional Landforms

Type Description
Terminal Moraine At glacier end
Lateral Moraine Along glacier sides
Medial Moraine Centre of glacier
Ground Moraine Spread over valley floor

Waves and Currents (NCERT Pages 57–59)

Coastal Processes

  • Waves are major coastal geomorphic agents.
  • Cause:
    • Erosion
    • Transportation
    • Deposition

Types of Coasts

Coast Type Characteristics
High Rocky Coast Erosional landforms dominate
Low Sedimentary Coast Depositional landforms dominate

Coastal Erosional Landforms

  • Sea cliffs
  • Wave-cut terraces
  • Sea caves
  • Sea stacks

Coastal Depositional Landforms

  • Beaches
  • Coastal dunes
  • Bars
  • Spits

Wind as a Geomorphic Agent (NCERT Pages 59–61)

Wind Action

  • Deflation
  • Abrasion
  • Impact

Desert Erosional Landforms

  • Pediments
  • Pediplains
  • Playas
  • Deflation hollows
  • Mushroom rocks

Sand Dunes

Type Features
Barchans Crescent-shaped dunes
Parabolic Dunes Vegetation-covered dunes
Seif One-winged dunes
Longitudinal Dunes Long ridges
Transverse Dunes Perpendicular to wind

Important Topics

Important Topic NCERT Page
Landscape evolution 47
Running water erosion 47–49
Valleys and canyons 48
Karst topography 52
Glacial landforms 54–57
Sand dunes 60–61

Important Geographical Concepts and Terms

Concept Explanation NCERT Page
Peneplain Nearly level plain formed by erosion 48
Gorge Deep narrow valley 48
Canyon Step-sided deep valley 48
Meander Loop-like river bend 51
Karst Topography Limestone landscape 52
Cirque Basin-like glacial hollow 54
Barchan Crescent-shaped dune 61

Important Questions

Very Short Answer Questions

  1. What is a landform? (NCERT Page 47)
  2. What is a peneplain? (NCERT Page 48)
  3. Define canyon. (NCERT Page 48)
  4. What are meanders? (NCERT Page 51)
  5. What is karst topography? (NCERT Page 52)
  6. Define stalactites. (NCERT Page 53)
  7. What is a cirque? (NCERT Page 54)
  8. What are moraines? (NCERT Page 55)
  9. What is a fjord? (NCERT Page 55)
  10. What are barchans? (NCERT Page 61)

Short Answer Questions

  1. Explain the stages of landscape evolution. (NCERT Pages 47–48)
  2. Differentiate between gorge and canyon. (NCERT Page 48)
  3. Explain formation of floodplains. (NCERT Pages 50–51)
  4. Describe karst topography. (NCERT Pages 52–53)
  5. Explain formation of stalactites and stalagmites. (NCERT Page 53)
  6. Describe glacial valleys. (NCERT Page 55)
  7. Explain coastal depositional landforms. (NCERT Pages 58–59)
  8. Describe wind action in deserts. (NCERT Pages 59–60)

Long Answer Questions

  1. Explain the role of running water in shaping landforms. (NCERT Pages 47–51)
  2. Describe erosional and depositional landforms formed by groundwater. (NCERT Pages 52–53)
  3. Explain glacial erosional and depositional landforms. (NCERT Pages 54–57)
  4. Describe coastal landforms formed by waves and currents. (NCERT Pages 57–59)
  5. Explain erosional and depositional landforms formed by wind. (NCERT Pages 59–61)

FAQs

1. What are geomorphic agents?

Agents like rivers, glaciers, waves and wind that shape Earth’s surface are geomorphic agents. (NCERT Page 47)

2. What is a meander?

A loop-like river bend formed due to lateral erosion is called a meander. (NCERT Page 51)

3. What is karst topography?

Karst topography is limestone landscape formed by groundwater action. (NCERT Page 52)

4. What are moraines?

Moraines are deposits left behind by glaciers. (NCERT Pages 55–56)

5. Which coast of India is depositional in nature?

The east coast of India is depositional in nature. (NCERT Page 58)

Quick Revision Summary

  • Landforms evolve through erosion and deposition.
  • Running water creates valleys and floodplains.
  • Canyons have step-like sides.
  • Meanders form due to lateral erosion.
  • Karst topography develops in limestone areas.
  • Stalactites hang from cave roofs.
  • Glaciers create U-shaped valleys.
  • Moraines are glacial deposits.
  • Waves form cliffs and beaches.
  • Wind action includes deflation and abrasion.
  • Pediplains are low-relief desert plains.
  • Barchans are crescent-shaped dunes.
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