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Concept Maps

Isostasy — Concept Maps

ICSE · Class 11 · Geography

4 concept maps of Isostasy for ICSE Class 11 Geography, each also written out as a text outline. Part of the ICSE Class 11 Geography syllabus.

43 questions36 flashcards3 formulas & key relations5 concepts

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4 Concept Maps

Isostasy: Complete Concept Overview

Isostasy: Complete Concept Overview

The map in words

  • Isostasy
    • Definition
      • Gravitational equilibrium
      • Equal mass beneath equal areas
      • State of balance
    • Historical Background
      • Bouguer 1735
      • Everest survey 1854
      • Dutton 1889 term coined
      • Airy Pratt 1855
    • Evidence for Theory
      • Plumb line deflection
      • Less than expected gravity
      • Crustal root observations
      • Seismic studies
    • Airy Concept
      • Floating blocks
      • Varying depth uniform density
      • Mountain roots
      • Hydrostatic equilibrium
    • Pratt Concept
      • Varying density uniform depth
      • Compensation level
      • Density inversely proportional
      • Mercury analogy
    • Crustal Layers
      • Sial light rocks
      • Sima dense rocks
      • Continental vs oceanic
      • Mohorovicic discontinuity
    • Modern Understanding
      • Holmes seismic evidence
      • Root confirmation
      • Crustal thickness variation
      • Temperature constraints
    • Applications
      • Isostatic rebound
      • Delta subsidence
      • Mountain stability
      • Earthquake prediction

Isostasy: Concept Overview and Key Components

Isostasy: Concept Overview and Key Components

The map in words

  • Isostasy Theory
    • Historical Development
      • Pierre Bouguer 1735
        • Andes Expedition
        • Plumb line deflection
      • Dutton 1889
        • First used term
        • American geologist
      • George Everest 1854
        • Indo-Gangetic survey
        • Himalayan observations
    • Core Concepts
      • Gravitational Equilibrium
        • Equal mass balance
        • Floating landforms
      • Crustal Composition
        • Sial layer
        • Sima layer
      • Compensation Level
        • Uniform density below
        • Variable above
    • Two Main Models
      • Airy Root Hypothesis
        • Varying root depths
        • Similar densities
        • Mountain roots
      • Pratt Density Model
        • Uniform depths
        • Varying densities
        • Inverse relationship
    • Supporting Evidence
      • Geodetic Surveys
        • Plumb line anomalies
        • Gravitational measurements
      • Seismic Studies
        • Crustal roots confirmed
        • Layer thickness mapping
      • Modern Technology
        • GPS measurements
        • Continuous monitoring
    • Applications
      • Mountain Formation
      • Crustal Subsidence
      • Ocean Basin Structure
      • Earthquake Understanding

Isostasy – Complete Concept Overview

Isostasy – Complete Concept Overview

The map in words

  • ISOSTASY
    • Definition and Origin
      • German word Isostasios
      • Meaning Equipoise
      • Coined by Dutton 1889
      • Gravitational equilibrium
    • Historical Evidence
      • Pierre Bouguer 1735
        • Andes Chimborazo
        • Less deflection than expected
      • Sir George Everest 1854
        • Kaliana to Kalianpur
        • 603 km apart
        • 5.23 vs 15.885 arc seconds
      • French Surveyors
        • Deflection away from mountains
        • Towards Bay of Biscay
    • Airy's Concept 1855
      • Sial floats on Sima
      • Same density 2.67
      • Varying depth roots
      • Iceberg analogy
      • Wooden block experiment
      • Root is 8 times height
      • Supported by Holmes and seismic data
    • Pratt's Concept 1855
      • Varying density
      • Same depth uniform
      • Height inversely proportional to density
      • Metal pieces in mercury
      • Mountains least dense
      • Oceans most dense
    • Holmes Views 1978
      • Supported Airy
      • Seismic evidence
      • Mountains 50 to 60 km roots
      • Coastal plains 30 km sial
      • Ocean floors no sial
    • Level of Compensation
      • Below this no density variation
      • Equal mass under equal areas
      • Airy roots end here
      • Pratt blocks bottom here

Isostasy

Isostasy

The map in words

  • Isostasy
    • Meaning of the term
    • Basic idea
    • Dutton
    • Pierre Bouguer
    • Sir George Everest
    • Plumb-line deflection
    • Kaliana and Kalianpur
    • Himalayan gravitational anomaly

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Frequently Asked Questions

What are the important topics in Isostasy for ICSE Class 11 Geography?
Key topics in Isostasy include Meaning and Basic Idea of Isostasy, Early Observations and Evidence, Airy's Concept of Isostasy, Pratt's Concept of Isostasy. Study these first, then practise questions on each for Class 11 exams.
What do the concept maps for Isostasy show?
The 4 maps show how the ideas in Isostasy connect: Isostasy: Complete Concept Overview; Isostasy: Concept Overview and Key Components. Each map is also written out as an outline on this page.
How should I revise Isostasy for Class 11 exams?
Learn the core ideas first, then work through the 43 practice questions on Isostasy. Revise definitions regularly and use flashcards for quick recall before the exam.

Sources & Official References

Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.

More resources for Isostasy

All ICSE Class 11 Geography Concept Maps

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