Landforms and their Evolution Class 11 Geography Chapter 6 CBSE Notes 2025-26

Landforms are the different physical forms or features on the surface of the Earth. Their formation and continuous change result from natural agents like running water, groundwater, glaciers, waves, and wind. These agents wear down materials through processes such as erosion and weathering, while deposition of eroded materials helps create new landforms. This cycle of erosion and deposition shapes the landscapes around us.

Several related landforms together make up a landscape. Every landform, whether it is a mountain, valley, plain, or plateau, has a unique development history that may change over time. The evolution of landforms occurs in stages, often likened to youth, maturity, and old age. During these stages, both natural forces and climate shifts can impact the size, shape, and materials of landforms.

Running water is a major agent of landform change, especially in regions with high rainfall. Water moves in two ways: overland flow in sheets and as streams or rivers in valleys. Erosion from running water can create distinctive landforms, and its power and speed vary depending on the land’s slope.

• Erosional landforms include valleys, gorges, canyons, potholes, plunge pools, incised or entrenched meanders, and river terraces.
• Depositional features created by running water are alluvial fans, deltas, floodplains, natural levees, point bars, and ox-bow lakes.

In the youthful stage of river development, deep V-shaped valleys, waterfalls, and few streams dominate. The mature stage has well-integrated streams, wider floodplains, and erosion shifts from vertical to lateral, reducing interstream areas. In the old stage, broad floodplains and meandering streams dominate, producing many levees and ox-bow lakes.

Groundwater is especially important where rocks contain calcium carbonate, such as limestone. Its action creates unique features known as karst topography. As water seeps underground, it dissolves the bedrock, forming pools, sinkholes, lapies (grooved limestone surfaces), and caves.

• Sinkholes are funnel-shaped depressions, often formed by the collapse of cave roofs.
• Many sinkholes can merge to form larger valley sinks or uvalas.
• Underground caves may have distinctive formations such as stalactites (hanging from the roof), stalagmites (rising from the floor), and pillars (when both meet).

Glaciers are massive bodies of moving ice, which shape the land through strong abrasion and the plucking of rocks. Their movement is slow but powerful, particularly in mountain valleys and polar regions. Glaciers create and later deposit a range of landforms.

• Erosional forms: Cirques (amphitheatre-shaped basins), arêtes (knife-edged ridges), horns (sharp peaks), U-shaped valleys or glacial troughs, hanging valleys, truncated spurs, and fjords (sea-filled glacial valleys).
• Depositional forms: Moraines (ridges of till including terminal, lateral, ground, and medial types), drumlins (oval hills), eskers (sinuous ridges), outwash plains (flat plains at glacier foot), and till (mixed-sized debris).

Coastal areas are shaped by the work of sea waves and currents. These agents cut, carry, and pile up materials, resulting in distinctive erosional and depositional coastal features. Coastlines can be high and rocky (submerged) or low and made of sediment (emerged).

• Erosional: Sea cliffs, terraces, sea caves at the base of cliffs, and isolated stacks formed by retreating cliffs.
• Depositional: Beaches (sediment strips along shore), bars (offshore sand ridges), spits (bars attached to the mainland at one end), lagoons (bodies of water cut off by spits), and dunes (sand mounds above beaches).

In dry desert regions, wind is a key agent, moving sand and dust to erode and deposit new features. Wind action leads to the removal of finer material (deflation) and the carving or abrasion of surfaces. Though wind is significant, occasional rain and gravity are also important.

• Erosional forms include pediments (gently sloping rock at the foot of hills), pediplains (broad flat areas), playas (shallow temporary lakes), deflation hollows, and unique mushroom or pedestal rocks shaped by wind abrasion.
• Depositional dunes: Barchans (crescent-shaped), parabolic dunes, seifs (elongated dunes due to shifting winds), longitudinal dunes (parallel ridges), and transverse dunes (ridges perpendicular to wind).

The transformation of earth’s surface through landform development involves three main stages: youth (active erosion and steep slopes), maturity (broad valleys, integrated drainage), and old age (nearly flat plains, slow river movement). Relief reduction and landform shaping depend on the continuous interplay between agents like water, wind, ice, and waves.

Important examination questions from this chapter focus on the differences between erosional and depositional features, processes that lead to the evolution of certain landforms, reasons for more underground flow in limestone terrains, characteristics of glacial deposition, and the relative impact of geomorphic agents in different climates. These are likely topics for short and long-answer sections.

Some key terms to remember include peneplain, monadnock, sinkhole, doline, fjord, esker, drumlin, spit, lagoon, playa, barchan, and arête. Knowing the process that forms each feature and being able to provide a simple definition or draw a labeled sketch can help in quick revision and better understanding of the concepts.

Identifying the landforms, materials, and processes in your area, such as nearby rivers, hills, or coastline, is also a recommended hands-on activity to reinforce these concepts.

Class 11 Geography Chapter 6 Notes – Landforms and Their Evolution: Key Revision Summary

These concise Class 11 Geography Chapter 6 notes on Landforms and Their Evolution are essential for quick revision and effective exam preparation. They explain crucial points on erosional and depositional features, making complex ideas easy for students to remember. Focused lists and definitions help you recall the stages and processes shaping earth’s landforms.

Use these Geography Class 11 revision notes to review key examples like valleys, deltas, moraines, dunes, and karst features. Understanding the evolution of landscapes, with all important terms clearly explained, will help you approach case-based and conceptual questions confidently. Grasp essential terms and processes with ease for your CBSE exams.