Erosion
Topic: Geomorphic Processes: Weathering, Mass Movement, Erosion and Soil Formation · NCERT: Class 9, Ch 2 "Shaping of the Earth's Surface"; Class 11, Ch 5 "Geomorphic Processes"
Meaning
Erosion is the picking up and carrying away of rock debris by moving agents: running water, groundwater, glaciers, wind and waves. These agents work through kinetic energy, the energy of motion. Debris carried by an agent scrapes and grinds surfaces, which is called abrasion, and this makes erosion much stronger. Weathering helps erosion by loosening rock, but weathering is not a precondition for it. Erosion is the main cause of continuous change on the earth's surface. It wears down high land, strips fertile topsoil, and damages homes and roads along rivers and coasts.
Example
The Chambal river and its streams have deeply eroded the soft soils along their banks in Madhya Pradesh, Rajasthan and Uttar Pradesh. The result is the badland ravines of the Chambal valley.
Don't confuse with
- Weathering: breaks rock in place (in situ). Erosion moves the broken material away.
- Mass movement: debris moves downslope by gravity alone, with no carrying agent, so it is not erosion.