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Difficulty: EasyLandform Evolution by Running Water and Underground Water

Which landform is produced in the upper course of a river when swirling eddy currents carrying pebbles grind cylindrical depressions into the riverbed bedrock?

  1. PotholesAnswer
  2. B
    Levees
  3. C
    Oxbow lakes
  4. D
    Stalagmites

Answer

Potholes are circular bedrock depressions created by the swirling action of river load (pebbles and gravel) driven by eddy currents in the upper course.
Potholes are smooth, cylindrical depressions carved into solid bedrock along a river channel. They form primarily in steep upper courses where swift-flowing water creates eddies that whirl pebbles around, drilling deep holes into bedrock depressions.

Step-by-Step Solution

1
Identify the process described in the stem.
The process described is pothole drilling (swirling river currents holding stone tools that erode bedrock).
Corrasion (abrasion) combined with eddy currents in swift-flowing water drills circular holes into irregularities in a stream bed.
2
Associate the process with its corresponding landform and course stage.
Potholes are distinctive erosional features of the upper (torrential) stage of a river.
High stream velocity and turbulent flow in steep upper courses provide the energy required for pebbles to carve circular hollows.

Key Concept

Fluvial Erosional Processes in the Upper Course
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Topics

Landform Evolution by Running Water and Underground Water

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