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Difficulty: Very hardRock Types, Formation, and Economic Importance

Match each geological material in Group I with its precise genesis and primary industrial application in Group II.

  • PumiceExtrusive vesicular pyroclastic rock utilized as a lightweight concrete aggregate and industrial abrasive.
  • DiatomiteSiliceous organically-formed sedimentary rock utilized as a high-grade filtration medium and chemical absorbent.
  • GraphiteCarbonaceous high-grade metamorphic mineral product utilized as a solid lubricant and crucible refractory material.
  • GypsumChemical evaporite sedimentary rock utilized as a retarder to control setting time in Portland cement.

Answer

Pumice pairs with extrusive vesicular pyroclastic rock used as a lightweight aggregate; Diatomite pairs with siliceous organically-formed sedimentary rock used as a filtration medium; Graphite pairs with carbonaceous metamorphic product used as a solid lubricant; Gypsum pairs with chemical evaporite sedimentary rock used as a cement setting retarder.
Each item is matched according to its fundamental rock classification group (Igneous pyroclastic, Organo-sedimentary, Metamorphic mineral, and Chemical evaporite) alongside its documented commercial utility in industrial geography.

Step-by-Step Solution

1
Analyze the formation process and economic role of Pumice
Pumice is an extrusive igneous rock with a vesicular texture formed by trapped volcanic gases, making it light enough to float and useful as an abrasive or lightweight concrete component.
Understanding volcanic texture differentiates extrusive pyroclastics from crystalline intrusive bodies.
2
Analyze the formation process and economic role of Diatomite
Diatomite is an organically derived sedimentary rock made of silica-based skeletal remains of diatoms, used extensively for industrial fluid filtration.
Siliceous organic sediment contrasts with calcareous organic sediment such as chalk or limestone.
3
Analyze the formation process and economic role of Graphite
Graphite forms under high-temperature/pressure metamorphic transformation of carbonaceous matter in sediments, yielding a soft, heat-resistant conductor and solid lubricant.
Metamorphic recrystallization alters organic carbon into pure crystalline carbon lattices.
4
Analyze the formation process and economic role of Gypsum
Gypsum forms via chemical precipitation in arid evaporite environments and serves as a crucial setting-time regulator in cement manufacture.
Evaporite minerals precipitate directly from concentrated hypersaline water.

Key Concept

Genesis, micro-structural characteristics, and industrial applications of igneous, sedimentary, and metamorphic rock types.
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Topics

Rock Types, Formation, and Economic Importance

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