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Difficulty: MediumWeathering and Mass Wasting Processes

In humid tropical regions with heavy seasonal rainfall, intense chemical alteration of granite bedrocks produces deep, clay-rich regolith layers in situ. Following a prolonged rainstorm, a large volume of this water-saturated regolith suddenly loses cohesion and moves rapidly downhill under the direct influence of gravity. Which of the following processes accounts for this rapid downhill movement of the saturated regolith?

  1. A
    Hydrolysis
  2. MudflowAnswer
  3. C
    Frost shattering
  4. D
    Metamorphic recrystallization

Answer

Mudflow
The scenario describes mass wasting where gravity pulls heavy, water-saturated weathered material down a slope. A mudflow specifically refers to the rapid movement of fine-grained, highly saturated regolith down steep slopes after intense rainfall.

Step-by-Step Solution

1
Distinguish between weathering and mass wasting mechanisms described in the scenario.
Chemical weathering (hydrolysis) formed the clay-rich regolith in situ, whereas gravity caused the subsequent downhill movement.
Weathering involves stationary breakdown, while mass wasting involves downslope displacement driven by gravity.
2
Identify the specific mass wasting type matching the movement characteristics.
A rapid movement of heavily saturated, fluid-like clay regolith following heavy rainfall is categorized as a mudflow.
Mudflows occur when fine-grained weathered material becomes saturated with water and rapidly flows down slopes.

Key Concept

Mass wasting processes vs. in-situ weathering
Estimated Time:1m 15s
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Topics

Weathering and Mass Wasting Processes

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