Geography Major Paper
Geomorphology & Economic Geography
Yeh textbook B.A. 5th Semester Geography Theory ke liye hai. Iss me Earth's Interior Structure (SIAL, SIMA, NIFE), Seismic Discontinuities (Moho & Gutenberg), Plate Tectonics Theory, Davisian Cycle of Erosion, Alfred Weber ka Material Index ($MI$) industrial location model, aur Indian Monsoon Mechanism ko aasan Hinglish me samjhaya gaya hai.
Earth Interior
SIAL, SIMA, NIFE & Discontinuities
Weber Location
Material Index MI Formula
Plate Tectonics
Convergent & Divergent Boundaries
Unit I
Geomorphology and Internal Structure
1.1
Internal Structure of the Earth & Seismic Discontinuities
Seismic wave velocity changes ($P$ and $S$ waves) provide empirical proof of the Earth's concentric layered structure:
| Layer / Boundary | Composition / Density | Key Physical Characteristics |
|---|---|---|
| Crust (SIAL) | Silica + Aluminium ($2.7 \, \text{g/cm}^3$). | Granitic continental crust and basaltic oceanic crust. |
| Moho Discontinuity | Crust-Mantle Boundary. | Abrupt increase in P-wave velocity from 6.9 to 8.1 km/s. |
| Mantle (SIMA) | Silica + Magnesium ($3.3 - 5.7 \, \text{g/cm}^3$). | Asthenosphere (100-200 km) serves as magma source for plate motion. |
| Gutenberg Discontinuity | Mantle-Core Boundary (2,900 km). | S-waves terminate completely (proves outer core is liquid). |
| Core (NIFE) | Nickel + Iron ($11 - 13 \, \text{g/cm}^3$). | Liquid outer core and solid dense inner core (Lehmann boundary). |
1.3
W.M. Davis Fluvial Cycle of Erosion (1899)
William Morris Davis postulated that landscape evolution is a function of Structure, Process, and Stage ("Triad of Davis"):
Three Stages of Landscape Evolution:
- Youth Stage: Rapid vertical downcutting, V-shaped valleys, gorges, waterfalls, and high relief.
- Mature Stage: Lateral erosion dominates; valley widening, river meanders, and maximum relief.
- Old Age Stage: Peneplanation; featureless plain (Peneplain) with isolated monadnock hills.
Unit III
Economic Geography and Location Theories
3.1
Alfred Weber's Least Cost Industrial Location Theory (1909)
Weber's Material Index (MI) Formula:
$$\text{MI} = \frac{\text{Weight of Localized Raw Material}}{\text{Weight of Finished Product}}$$
Industrial Location Rules:
- If $\text{MI} > 1$ (Weight-Losing Raw Material): Industry locates near raw material source (e.g., Sugar mills, Iron & Steel).
- If $\text{MI} = 1$ (Pure Raw Material): Industry can be located anywhere between source and market (e.g., Cotton textiles).
- If $\text{MI} < 1$ (Weight-Gaining Material): Industry locates near the consumption market (e.g., Beverage bottling).
Exam Special
Examination Question Bank & Revision Tools
Quick Revision Flashcards
What is the formula for Material Index (MI)?
MI = Weight of Localized Raw Material / Weight of Finished Product.
What boundary separates Crust from Mantle?
Mohorovičić (Moho) Discontinuity.
What end landform does Davis predict?
Peneplain with Monadnocks.
Practice MCQs
Q1. In Alfred Weber's theory, if Material Index MI > 1, where should the factory be located?
Explanation: When MI > 1, raw materials lose weight in production, so locating near the raw material source minimizes transport costs.
Key Terms Glossary
Moho Discontinuity
Boundary separating the Earth's crust from the mantle.
Peneplain
Low-relief featureless plain representing the final stage of fluvial erosion.