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Difficulty: MediumOceans, Coastal Processes, and Coastal Landforms

Match each coastal marine process listed in Column A with its corresponding geomorphic action described in Column B.

  • Hydraulic actionCompression and expansion of trapped air in cliff joints by breaking wave force
  • Corrasion (Abrasion)Scouring and scraping of cliff faces by rock fragments hurled by wave energy
  • Longshore driftLateral movement of beach sediment along the coast via swash and backwash
  • AttritionMutual wearing down and rounding of rock fragments colliding in turbulent water

Answer

Hydraulic action matches compression and expansion of trapped air in cliff joints; Corrasion matches scouring and scraping of cliff faces by rock fragments; Longshore drift matches lateral movement of beach sediment along the coast; Attrition matches mutual wearing down and rounding of rock fragments colliding in turbulent water.
Hydraulic action is driven by water pressure compressing trapped air in cliff joints; corrasion uses wave-hurled rock tools to scour cliff surfaces; longshore drift transports beach load laterally through swash and backwash cycles; attrition rounds and reduces sediment particle sizes through mutual collisions.

Step-by-Step Solution

1
Analyze the mechanical effect of wave impact and air compression on cliff joints.
Trapped air compressed in rock crevices exerts immense hydraulic force, causing rock loosening and disintegration (Hydraulic Action).
Wave shock pushes air deep into cracks, creating explosive expansion when the wave recedes.
2
Distinguish between abrasive action on cliff faces versus particle collision within wave load.
Rock fragments hitting the cliff face act as abrasive tools (Corrasion), whereas rock fragments colliding with each other reduce in size and sharpen/round off (Attrition).
Corrasion erodes the mainland rock structure, while attrition alters the physical characteristics of the transported load itself.
3
Identify the process responsible for transport of coastal sediment along a beach.
The combined angled swash and straight backwash move sediment laterally along the shoreline (Longshore Drift).
Wind direction dictates the angle of wave approach, while gravity pulls water back straight down the slope of the beach.

Key Concept

Coastal Marine Processes and Mechanisms
Estimated Time:1m 0s
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Topics

Oceans, Coastal Processes, and Coastal Landforms

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