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Difficulty: MediumWeathering and Mass Wasting Processes

In a humid tropical environment, acidic groundwater reacts with orthoclase feldspar present in granite bedrock. Through a reaction where hydroxyl (OH−OH^-) and hydrogen (H+H^+) ions replace potassium cations, the hard rock is decomposed in-situ into soft kaolin clay. Which chemical weathering process does this transformation describe?

  1. HydrolysisAnswer
  2. B
    Solifluction
  3. C
    Metamorphic recrystallization
  4. D
    Slumping

Answer

Hydrolysis
Hydrolysis is the chemical weathering process wherein water molecules dissociate into hydrogen (H+H^+) and hydroxyl (OH−OH^-) ions that replace mineral cations (such as potassium in orthoclase feldspar), breaking down granite in-situ into kaolin clay.

Step-by-Step Solution

1
Analyze the process described in the scenario
The scenario describes an in-situ chemical reaction where ions from groundwater (H+H^+ and OH−OH^-) react with feldspar in granite, altering it into kaolin clay.
Chemical weathering involves chemical reactions that alter the mineral composition of rocks at or near the surface.
2
Identify the specific chemical weathering mechanism
Hydrolysis specifically describes the reaction between water ions and silicate minerals like feldspar to form clay minerals.
Mass wasting processes involve downslope displacement under gravity, while metamorphism occurs deep underground under extreme heat/pressure.

Key Concept

Chemical weathering of silicate minerals via Hydrolysis
Estimated Time:1m 0s
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Topics

Weathering and Mass Wasting Processes

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