Landforms on Earth and External Processes

There are various landforms on earth. By now, you would know about the internal factors that have an impact on them. But do you know what are the external factors that have an impact on them? Let’s find out more about Landforms on Earth and External Processes.

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Landforms on Earth

Any natural feature of the solid surface of the earth or any other planetary body is a landform. Usually, they are in the form of hills, mountains, plains, valleys, plateaus, canyons, shorelines, volcanoes, etc.

Physical attributes such as elevation, slope, orientation, stratification, rock exposure, and soil type decided the characteristics of a landform. Landforms together make up a given terrain, and their arrangement in the landscape is known as topography.

Browse more Topics under General Physical Geography

• What is Geography
• Landforms of the Earth and Internal Forces
• Physical Features of Geography

External Processes

Some of the external processes that have an impact on landforms are:

• Denudation: Denudation is a process where the wearing away of the surface of the earth is caused due to moving water, by ice, by wind, and by waves, leading to a reduction in elevation and in relief of landforms and of landscapes. Weathering and Erosion are parts of denudation.
• Deposition: Deposition is the geological process in which sediments, soil, and rocks are added to a landform or land mass. It can be caused by water, ice, wind, living organisms, evaporation, precipitation, etc. Deposition of organic matter may also affect the landforms.

Questions For You

Q1. Which one of the following combinations of stalactites arid stalagmites occurrences is correct?

1. Stalactites hang as icicles of different diameters and stalagmites hanging from the floor of the caves.
2. Stalactites hang as icicles of different diameters and stalagmites rise up from the floor of the caves.
3. They rise up from the floor of the caves and stalagmites hang as icicles of different diameters
4. Stalactites hang as icicles of different diameters and stalagmites also hang as icicles of different diameters.

Sol. The correct answer is the option ”b”. Stalactites and stalagmites are both rock formations which may be composed of minerals, lava, sand, pitch etc. Stalactites hang as icicles from the ceilings of the caves and may be of different diameters. Stalagmites rise from the floor of the caves and are formed due to an accumulation of material dropped from the stalactites.

Q2. With respect to chemical weathering a denudational process, choose the correct statements

1. It may weaken or entirely dissolve certain constituent of rocks.
2. In granite, which is made up of quartz feldspar and mica, feldspar easily weathers away.
3. A loosened material, as in the example of granite, quartz and mica are eroded.
4. A weathered material as in case of granite, feldspar forms regolith, basis of soil.

1. 1 and 2
2. 2 and 3
3. 1, 2 and 3
4. All of the above

Sol: The correct answer is the option ”d”. Chemical weathering may weaken or dissolve certain constituent of rocks. In granite, which is made up of quartz feldspar and mica, feldspar easily weathers away. A loosened material, as in the example of granite, quartz and mica are eroded. A weathered material as in case of granite, feldspar forms regolith, basis of soil.