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SURAMYA SHARMAAIR 359· 2025

Question Q15GS1GS1

Discuss the concept of isostasy and explain its role in shaping Earth's major landforms.

Open scan (p.33)

Introduction

Isostasy is a phenomenon which explains the adjustments of Earth's crust dimensions and subsiding gravity values.

16 words

Main Body

Isostasy is a phenomenon which explains the adjustments of Earth's crust dimensions and subsiding gravity values.

Concept of Isostasy:

1Airy's theory explains isostasy thought concept of buoyancy.

i) Crust had uniform velocities and varying depths related to thickness of crust.

ii) The crust - buoyed up, thick crust - more down.

eg: mountains

2Pratt's theory explains isostasy through uniform density of compression - but varying density.

How the phenomenon is called Isostasy.

5Plate tectonics theory:

i) Regional root formation due to smelting of earth's crust due to overlying crustal landform.

ii) Deposition leads to smelting

iii) Erosion leads to uplift to maintain balance.

The phenomenon is called Isostasy.

Role in shaping Earth's major landforms:

1Isostatic uplifts reshape landforms, eg; Scandinavia upon due to mixing of sea glaciers. (Annot part of VASA uplift)

Isostasy helps to analyze the crustal change in landforms which can be helpful to analyze landform development.

153 words7 paragraphs

Conclusion

Isostasy helps to analyze the crustal change in landforms which can be helpful to analyze landform development.

17 words

Diagram

Diagram showing plate tectonics, isostatic adjustment, and landform changes with mountain formation and erosion processes

  • Clear conceptual definition
  • Presents two major theories (Airy and Pratt)
  • Includes diagram for illustration
  • Explains principle of buoyancy
  • Introduces plate tectonics theory
  • Provides real-world example (Scandinavia)
  • Shows cyclical nature of erosion and uplift
  • Diagrams support concept

Topper

SURAMYA SHARMA

AIR 3592025

Subject & Paper

GS1GS1

Topic

Salient features of World's Physical Geography

Geophysical Phenomena

Isostasy and Landform Development

Writing Stats

186

Total words

7

Paragraphs

explanatory and analytical

Tone