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Difficulty: MediumMineral Resources and Mining in Africa

Guinea possesses one of the world's largest reserves of high-grade bauxite. Which geological process is primarily responsible for the formation and concentration of these extensive bauxite deposits across the country's plateau landscapes?

  1. Deep chemical weathering and leaching of aluminum-rich rocks under humid tropical conditionsAnswer
  2. B
    Sedimentation and compaction of organic plant debris in ancient low-lying lacustrine basins
  3. C
    Crystallization of minerals from magmatic intrusions within Precambrian basement complexes
  4. D
    Precipitation of dissolved salts following the complete evaporation of inland saline lakes

Answer

Deep chemical weathering and leaching of aluminum-rich rocks under humid tropical conditions
Bauxite is a residual deposit created by deep chemical weathering (lateritization) under warm, wet tropical climates. Intense leaching washes away silica and alkali bases from aluminum-bearing parent rocks, leaving behind concentrated hydrous aluminum oxides on stable plateaus.

Step-by-Step Solution

1
Identify the mineral nature and formation environment of bauxite.
Bauxite is a residual ore composed chiefly of hydrous aluminum oxides.
It is not a primary igneous or sedimentary rock, but a product of weathered mantle rocks.
2
Analyze how tropical weathering concentrates aluminum minerals in Guinea.
High annual rainfall and warm temperatures accelerate lateritization.
Soluble compounds such as silica, calcium, and sodium are leached downward out of aluminum-bearing silicate parent rocks, leaving a residual crust of insoluble aluminum minerals on flat, stable plateaus.

Key Concept

Bauxite Formation and Tropical Lateritization in Africa
Estimated Time:1m 0s
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Topics

Mineral Resources and Mining in Africa

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