Major Landforms of the Earth

Major Landforms of the Earth

The surface of the Earth is constantly being shaped and reshaped by natural processes. Two key processes are responsible for changing the landscape:

1. Weathering – The breaking down of rocks into smaller pieces by natural forces such as temperature change, plants, animals, and chemicals.

2. Erosion – The wearing away of the landscape by moving agents such as water, wind, and ice.

After erosion, the eroded material is transported by these agents and eventually deposited elsewhere. The combined effect of erosion and deposition creates various major landforms.

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1. Work of a River

Rivers shape the land in three stages – upper course (erosion), middle course (erosion & deposition), and lower course (deposition).

A. Waterfalls

• Formed when a river flows over hard rock followed by softer rock, causing the softer rock to erode faster.

• Waterfalls are steep drops in the river’s course.

• Examples:

  • Angel Falls – Venezuela (Highest in the world)

  • Niagara Falls – On the Canada–USA border

  • Victoria Falls – On the Zambia–Zimbabwe border

B. Meanders and Ox-bow Lakes

• Meander: Large bends formed by a river in its middle and lower course due to lateral erosion.

• Over time, erosion on the outer banks and deposition on the inner banks make the loop sharper.

• Eventually, the loop is cut off, forming an ox-bow lake.

C. Floodplains and Levees

• During floods, rivers overflow their banks and deposit fertile alluvial soil, creating floodplains.

• Raised banks of deposited material along the river are called levees.

D. Delta Formation

• At the river’s mouth, speed decreases, and the river splits into distributaries.

• Deposition at the mouths forms a triangular or fan-shaped delta.

• Example: The Ganga–Brahmaputra Delta.

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2. Work of Sea Waves

Sea waves continuously erode and deposit material along coastlines, creating distinct coastal landforms.

• Sea Caves: Formed when waves erode cracks in coastal rocks.

• Sea Arches: When waves erode through a cave, leaving an arch-shaped opening.

• Stacks: When the roof of a sea arch collapses, leaving an isolated vertical rock column.

• Sea Cliffs: Steep rocky coasts rising sharply from the sea.

• Beaches: Formed when sea waves deposit sand and pebbles along the shore.

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3. Work of Ice (Glaciers)

Glaciers are “rivers of ice” that move slowly but have powerful erosive force.

• They erode by bulldozing soil and rocks, carving out deep hollows.

• When the ice melts, these hollows become lakes.

• Deposited material (rocks, gravel, sand) forms glacial moraines.

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4. Work of Wind

Wind is an active erosional and depositional agent in desert regions.

• Mushroom Rocks: Formed when wind erodes the lower parts of a rock faster than the upper parts, creating a narrow base and wider top.

• Sand Dunes: Low hills of sand formed by wind deposition.

• Loess: Fine, light sand particles carried over long distances and deposited in thick layers.

  • Example: Large loess deposits in China.

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5. Summary Table – Agents of Landform Formation

Agent	Erosional Landforms	Depositional Landforms
River	Waterfalls, Meanders	Floodplains, Levees, Delta
Sea Waves	Sea Caves, Arches, Stacks, Cliffs	Beaches
Glaciers	Glacial valleys, hollows	Moraines
Wind	Mushroom rocks	Sand dunes, Loess

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Conclusion

The Earth’s surface is in a state of continuous transformation. Rivers, sea waves, glaciers, and wind constantly modify the landscape through erosion, transportation, and deposition. These processes give rise to spectacular natural features, many of which have significant economic, environmental, and cultural value.