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Question

Difficulty: HardRock Types, Formation, and Economic Importance

Match each rock type or mineral deposit in Column I with its correct geological formation process and primary economic usage in Column II.

  • KimberliteUltramafic igneous rock occurring in deep volcanic pipes, serving as the primary commercial source of natural diamonds
  • BauxiteResidual sedimentary rock produced by intense tropical weathering and leaching, serving as the principal ore of aluminum
  • MarbleMetamorphic rock formed from thermal or regional alteration of limestone, widely utilized in statuary and decorative building
  • DolomiteSedimentary carbonate rock rich in magnesium carbonate, used as a building stone and in the manufacture of cement and refractories

Answer

Kimberlite matches ultramafic volcanic pipe igneous rock (diamond source); Bauxite matches residual sedimentary rock formed via tropical leaching (aluminum ore); Marble matches thermal metamorphic recrystallized limestone (decorative building stone); Dolomite matches magnesium-bearing sedimentary carbonate rock (cement and refractory production).
Each rock is matched precisely to its mode of formation and primary economic application: Kimberlite is an intrusive igneous rock containing diamonds; Bauxite is a residual sedimentary rock that serves as aluminum ore; Marble is a metamorphic rock recrystallized from limestone used in ornamentation; Dolomite is a magnesium-rich sedimentary rock used in industrial construction.

Step-by-Step Solution

1
Analyze Kimberlite origin and economic value.
Kimberlite is an intrusive, ultramafic igneous rock forming narrow volcanic pipes. It is famous worldwide as the primary economic source of natural diamonds.
Igneous rock classifications link deep mantle plutonic/volcanic features with specific heavy mineral deposits.
2
Analyze Bauxite formation mechanism.
Bauxite is a residual sedimentary deposit created when prolonged chemical leaching in hot, wet climates washes away soluble minerals, leaving concentrated aluminum oxide.
Residual rocks are classified under surface sedimentary processes driven by weathering rather than deep thermal metamorphic forces.
3
Evaluate Marble metamorphic parentage.
Marble is formed when existing limestone undergoes heat and pressure, causing calcite minerals to recrystallize into a denser, polished decorative stone.
Identifying the parent rock (protolith) clarifies the transition from sedimentary carbonate to metamorphic rock.
4
Evaluate Dolomite sedimentary characteristics.
Dolomite is a sedimentary rock formed when magnesium replaces part of the calcium in limestone or precipitates directly in saline marine environments.
Chemical and biochemical sedimentary processes yield distinct magnesium-rich mineral compositions valuable in metallurgy and construction.

Key Concept

Classification of Rock Origins (Igneous, Sedimentary, Metamorphic, Residual) and Economic Minerals
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Topics

Rock Types, Formation, and Economic Importance

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