UPSC MainsGEOGRAPHY-PAPER-I201610 Marks150 Words
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Q1.

Describe the "Basket of eggs topography".

How to Approach

This question requires a descriptive answer focusing on a specific landform – the ‘Basket of Eggs Topography’. The approach should involve defining the landform, explaining its formation through differential erosion, detailing its characteristics, and providing geographical examples. Structure the answer by first defining the term, then explaining the geological processes involved, followed by describing the resulting landscape features, and finally, citing locations where this topography is observed. Focus on clarity and conciseness within the 150-word limit.

Model Answer

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Introduction

The ‘Basket of Eggs Topography’, also known as ‘Rogenlands’, is a unique erosional landform characterized by closely spaced, rounded hills resembling eggs in a basket. This distinctive landscape is primarily found in areas underlain by horizontally bedded sedimentary rocks, particularly those with alternating layers of hard and soft rock. The formation of this topography is a result of differential erosion, where more resistant rock layers protect underlying softer layers, leading to the creation of these undulating hills. It’s a classic example of how geological structure influences landform development.

Formation and Characteristics

The process begins with horizontally stratified rocks – typically sandstone and shale. The more resistant sandstone forms the rounded hilltops, while the softer shale erodes more readily, creating the intervening valleys. This differential erosion is further enhanced by weathering and fluvial action.

Key Features:

  • Rounded Hills: The hills are typically dome-shaped or rounded due to the protective effect of the harder sandstone.
  • Closely Spaced Valleys: The valleys are narrow and closely spaced, giving the appearance of a basket holding eggs.
  • Uniform Slope: The overall slope of the landscape is relatively uniform.
  • Lack of Drainage: Often, surface drainage is poorly developed due to the permeability of the sandstone.

Geographical Examples

Classic examples of Basket of Eggs Topography are found in:

  • Pennsylvania, USA: The Appalachian Plateau region exhibits well-developed Rogenlands.
  • Germany (Harz Mountains): Similar landscapes are observed in the Harz Mountains.
  • Ireland: Parts of County Clare display this topography.

The specific rock types and climatic conditions influence the scale and characteristics of the landform in each location. For instance, areas with higher rainfall experience more rapid erosion, leading to more pronounced valleys.

Conclusion

In conclusion, the Basket of Eggs Topography is a compelling example of how differential erosion sculpts landscapes. Its formation is intrinsically linked to horizontally bedded sedimentary rocks and the varying resistance of their constituent layers. Understanding this landform provides valuable insights into the interplay between geological structure, erosional processes, and the resulting landscape features, showcasing the dynamic nature of Earth’s surface.

Answer Length

This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.

Additional Resources

Key Definitions

Differential Erosion
Differential erosion refers to the varying rates of erosion of different rock types or structures due to differences in their resistance to weathering and erosion.
Rogenland
Rogenland is a Scandinavian term used synonymously with ‘Basket of Eggs Topography’, referring to a landscape of closely spaced, rounded hills formed by differential erosion.

Key Statistics

The Appalachian Plateau, where prominent Rogenlands are found, covers approximately 140,000 square miles across several US states.

Source: US Geological Survey (USGS) - Knowledge cutoff 2023

Sandstone constitutes approximately 20-25% of all sedimentary rocks, making it a common rock type in areas exhibiting Basket of Eggs topography.

Source: Robert H. Dott Jr., and Roger L. Bangs, *Heavy Minerals in Beach Sediments* (1983) - Knowledge cutoff 2023

Examples

Schunemunk Mountain, New York

Schunemunk Mountain in New York State provides a clear example of Basket of Eggs topography, showcasing the rounded hills and closely spaced valleys formed by the erosion of Shawangunk conglomerate and sandstone.

Frequently Asked Questions

What is the primary driving force behind the formation of Basket of Eggs topography?

The primary driving force is differential erosion, specifically the varying resistance of horizontally bedded sedimentary rocks to weathering and erosion. Harder rocks protect softer rocks, leading to the characteristic rounded hills and valleys.

Topics Covered

GeomorphologyPhysical GeographyErosionLandformsTopography