Erosion and Deposition

Definition

Erosion is the wearing away and removal of rock and soil by moving agents (rivers, glaciers, wind, waves, and groundwater); deposition is the laying down of that transported material when the agent loses energy.

Key points

• The main agents of erosion are running water (rivers), glaciers (ice), wind (aeolian action), sea waves, and underground water; each carves distinctive landforms.
• River erosion happens by hydraulic action, abrasion (corrasion), attrition, and solution (corrosion); the same forces apply with modification to other agents.
• Erosion dominates in the upper course of a river and on highlands; deposition dominates in the lower course, on plains, and in basins.
• Deposition builds constructive landforms such as deltas, floodplains, sand dunes, beaches, and moraines.
• Soil erosion (loss of fertile topsoil by sheet, rill, and gully erosion) is a major land-degradation problem in India, especially the Chambal ravines.

Why it matters for CAPF

The list of erosional agents, the river-erosion processes, and the erosion-versus-deposition zones along a river are recurring geomorphology items; soil erosion links to land degradation and the environment.

Common confusion

Erosion (removal and transport) versus weathering (breakdown in place); abrasion (rubbing by load) versus attrition (load fragments wearing each other); erosion upstream versus deposition downstream.

Parent note

geomorphology earth interior and plate tectonics