Factors Controlling Landform Development | Geography Optional for UPSC (Notes) PDF Download

What are Landforms?

• Landforms are three-dimensional structures found on the Earth's surface, ranging from small to medium-sized areas. These natural formations can take various shapes, such as mountains, plains, plateaus, valleys, and hills, among others.

Before going to the factors that control the development of landforms, we need to know the answers to some of the main questions like -

Why do landforms develop? Why is the Earth's surface uneven?

• The Earth's crust is constantly moving, both vertically and horizontally. This movement contributes to the formation and reshaping of various landforms over time.
• The geothermal gradient, or the variation in the Earth's internal heat, causes uneven distribution of energy within the planet. This energy generates internal forces that create different types of high and low land surfaces, which are collectively known as landforms.
• External forces, primarily driven by sunlight, also influence the Earth's surface. These forces include weathering, erosion, and mass movement, which alter the structure of landforms over time. For instance, large mountains may gradually erode into smaller hills and eventually become flat plains due to the continuous action of these external forces.
• The intensity of both internal and external forces varies across the Earth's surface. This variation leads to the development of diverse landforms in different regions.

In summary, the development of landforms and the unevenness of the Earth's surface are primarily due to the dynamic nature of the Earth's crust and the varying intensities of internal and external forces. Other factors also contribute to the formation and evolution of landforms, but these primary forces play a significant role in shaping the Earth's diverse landscapes.

Following are the controlling factors of landform development:

• Rock Composition or Parent Rocks: The rate at which landforms develop or form is influenced by their rock composition or parent rocks. This is due to the variation in the size and composition of rocks, which determines their hardness or softness. For example, quartz is a hard rock that erodes and weathers slowly, while limestone is a soft rock that undergoes weathering and erosion more quickly. This results in the rapid degradation of landforms composed of softer rocks. Each rock type has unique characteristics that make it more or less resistant to different weathering agents, leading to the formation of diverse landforms.
• Relief:  Relief refers to the elevation difference between the highest and lowest points in an area. Landforms develop more quickly in areas with greater relief due to increased erosion. For instance, landform development in the Himalayan region is faster than in the Aravalli region because the relief is higher. Greater relief also results in stronger gravitational forces, leading to mass movements and large-scale landslides.
• Geological Formation: The geological structure of rocks, such as their layers, faults, orientations, inclinations, joint presence or absence, hardness or softness, and chemical sensitivity, also affects landform development.
• Exogenous Agents: External factors like water, wind, ice, currents, waves, and tides also influence the development process of landforms.
• Climate: Temperature and humidity are crucial climate factors that impact landform development. High humidity enhances chemical and biological weathering processes, while high rainfall and wind speeds increase erosion activities. Large temperature variations cause rocks to expand and contract, leading to their fragmentation. Landform development processes and intensities vary across different climatic zones and even within the same climate zone due to varying rainfall and temperature intensities.
• Energy: Energy sources, both internal and external, affect landform development. Internal energy refers to differences between convergent and divergent convection cells within the Earth, while external energy includes temperature variations, wind, and pressure changes.
• Biological Activities: The presence of vegetation can accelerate chemical weathering processes as plants release acids and moisture onto rocks. Conversely, a lack of vegetation can increase erosion, leading to the rapid degradation of elevated landforms.
• Human Activities: Human actions, such as agriculture, dam construction, infrastructure development, and brick-making, can also influence landform development.

Conclusion

Frequently Asked Questions (FAQs) of Factors Controlling Landform Development

What are the main types of landforms?

Some of the main types of landforms include mountains, plains, plateaus, valleys, and hills. These natural formations vary in size and shape and are found on the Earth's surface.

What are the internal and external forces that contribute to landform development?

Internal forces include the movement of the Earth's crust and the geothermal gradient, which generates energy that shapes the Earth's surface. External forces, driven by sunlight, include weathering, erosion, and mass movement, which alter the structure of landforms over time.

How does rock composition affect landform development?

The rock composition or parent rocks influence the rate of landform development due to the variation in the size and composition of rocks, which determines their hardness or softness. Harder rocks like quartz erode and weather slowly, while softer rocks like limestone undergo weathering and erosion more quickly.

How does climate influence landform development?

Temperature and humidity are crucial climate factors that impact landform development. High humidity enhances chemical and biological weathering processes, while high rainfall and wind speeds increase erosion activities. Large temperature variations cause rocks to expand and contract, leading to their fragmentation.

How do human activities affect landform development?

Human actions, such as agriculture, dam construction, infrastructure development, and brick-making, can influence landform development by altering natural processes like erosion and weathering. These activities can lead to the rapid degradation of elevated landforms and the alteration of the Earth's surface.