Concept:Oxbow lakes are formed by both erosion (on the outer banks of meanders) and deposition (on the inner banks), eventually cutting off a meander loop.
Explanation:A river in its plains develops large bends called meanders due to lateral erosion and deposition.
On the outer curve of a meander, erosion is strong, deepening and widening the bend.
On the inner curve, deposition builds up sediment, making the bend narrower.
Over time, the meander loop becomes so tight that the river cuts through the narrow neck during a flood.
The river then takes a new, straighter path.
The abandoned meander loop gets sealed off by sediment deposition at both ends.
This isolated water body is called an oxbow lake.
Thus, both erosion (cutting the neck) and deposition (sealing the ends) are involved.
Other features:
• Pothole: formed only by erosion (abrasion) in riverbed.
• Levee: formed only by deposition (when river overflows and deposits sediment on banks).
• Rapids: formed by erosion in hard rock zones.
Only oxbow lake requires both erosion and deposition in its formation.
Answer:Oxbow lake
