The key difference between erosional and coastal plains lies in their formation: erosional plains are created by the wearing down of land over time, while coastal plains are formed by the uplift of the seafloor or the accumulation of sediments near the coast.
Erosional Plains
- Formation: These plains, sometimes called peneplains, result from prolonged weathering and erosion that reduces mountains or plateaus to low-lying, relatively flat surfaces. The process takes an extremely long time.
- Process: Wind, water, ice, and other erosive forces gradually break down the existing landforms.
- Example: The landscape of parts of northern Canada showcases features resulting from glacial erosion.
Coastal Plains
- Formation: Coastal plains are created either by the uplift of a portion of the seafloor bordering a continent or by the accumulation of sediments (like sand, silt, and clay) brought down by rivers and deposited along the coast.
- Process: In uplifted coastal plains, tectonic forces raise the seafloor. In depositional coastal plains, rivers deposit sediment over time, gradually extending the land outwards.
- Example: The Atlantic Coastal Plain of the eastern United States is a well-known example of a coastal plain formed by both uplift and deposition.
Summary Table
| Feature | Erosional Plain | Coastal Plain |
|---|---|---|
| Formation | Weathering and erosion of existing landforms | Uplift of seafloor or deposition of sediments at coast |
| Process | Wearing down | Uplift or Sediment Accumulation |
| Location | Can be inland | Always near the coast |
