Chapter 6: Landforms and their Evolution
Geography - Fundamental of Physical Geography • Class 11
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Chapter Analysis
Intermediate14 pages • EnglishQuick Summary
The chapter on 'Landforms and their Evolution' explores the dynamic processes that shape the Earth's surface, focusing on various geomorphic agents like water, glaciers, winds, and waves. It discusses both erosional and depositional landforms, emphasizing how each landform has a history of development influenced by environmental factors and geomorphic processes. The chapter also introduces stages of landform development, paralleling them with youth, maturity, and old age, and highlights specific landscapes like deserts and coastal regions to explain these processes.
Key Topics
- •Geomorphic agents and processes
- •Erosional and depositional landforms
- •Stages of landform development
- •Glacial and coastal landforms
- •Desert landforms and wind erosion
- •Impact of water on landscape transformation
- •Karst topography features
Learning Objectives
- ✓Understand the processes and agents responsible for shaping landforms.
- ✓Identify different types of landforms and their characteristics.
- ✓Explain the evolution of landforms through various stages.
- ✓Assess the impact of climatic and environmental changes on landform evolution.
- ✓Distinguish between different erosional and depositional features.
- ✓Explore specific landform examples from various regions such as deserts and coastal areas.
Questions in Chapter
In which of the following stages of landform development, downward cutting is dominated?
Answer: Youth stage
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A deep valley characterised by steep step-like side slopes is known as
Answer: Canyon
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In which one of the following regions the chemical weathering process is more dominant than the mechanical process?
Answer: Limestone region
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Which one of the following sentences best defines the term ‘Lapies’ ?
Answer: An irregular surface with sharp pinnacles, grooves and ridges
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A deep, long and wide trough or basin with very steep concave high walls at its head as well as in sides is known as:
Answer: Cirque
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What do incised meanders in rocks and meanders in plains of alluvium indicate?
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Explain the evolution of valley sinks or uvalas.
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Underground flow of water is more common than surface run-off in limestone areas. Why?
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Glacial valleys show up many linear depositional forms. Give their locations and names.
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How does wind perform its task in desert areas? Is it the only agent responsible for the erosional features in the deserts?
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Running water is by far the most dominating geomorphic agent in shaping the earth’s surface in humid as well as in arid climates. Explain.
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Additional Practice Questions
Describe the process of formation of a delta.
mediumAnswer: A delta forms when sediment carried by a river is deposited as the water enters a standing body of water like a sea or lake. The sediment builds up over time, creating a landform that often includes multiple distributary channels flowing into the standing water.
What are the primary differences between glacial and river valleys?
mediumAnswer: Glacial valleys are typically U-shaped, created by the glacier's movement through a valley, while river valleys are V-shaped, formed by the erosional power of water flowing through them.
Explain the formation of a sand dune in desert regions.
hardAnswer: Sand dunes form through the accumulation of sand blown by the wind, which settles when it encounters an obstacle. Over time, this deposited sand piles up to form dunes, which can be molded by wind direction and speed.
How does a meander form and evolve in a river?
easyAnswer: Meanders form as water in a river erodes the outer banks and deposits silt on the inner bends, causing the river to curve. Over time, these curves can become more pronounced and even lead to the creation of oxbow lakes.
What role does weathering play in the formation of landforms?
mediumAnswer: Weathering breaks down rocks into smaller particles through mechanical, chemical, or biological processes, which can then be transported and deposited to form new landforms such as soil layers and sedimentary landforms.
Compare and contrast erosional features such as cliffs and canyons.
mediumAnswer: Cliffs are steep faces of rock and earth formed primarily by erosion and weathering, while canyons are deep, narrow valleys with steep sides, typically carved by river erosion.
Discuss the impact of human activities on landform evolution.
hardAnswer: Human activities, like deforestation, mining, and urbanization, dramatically alter landforms by changing erosion patterns, increasing sedimentation rates, and reshaping landscapes directly through excavation and construction.
What are moraines, and how do they form?
easyAnswer: Moraines are accumulations of dirt and rocks that have been left behind by a moving glacier. They typically form at the sides (lateral moraine), middle (medial moraine), and the end (terminal moraine) of glaciers.
Explain the concept of a 'youthful' landscape in geomorphology.
mediumAnswer: A youthful landscape is characterized by steep gradients, a high rate of erosion, V-shaped valleys, and a lack of floodplains. These features indicate early stages of landscape development dominated by vigorous water flow.
How do floods affect floodplain development?
easyAnswer: Floods contribute to floodplain development by depositing layers of sediment, which can build up over time to create broad, flat areas adjacent to a river. These deposits increase soil fertility and alter the landscape to facilitate diverse ecosystems.