Weathering And Erosion - Types & Difference | NCERT Notes

WEATHERING & EROSION

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WEATHERING

Weathering is an in situ process in which rocks break into small particles due to the weather. It does not involve the removal of rock material.

Heat, cold, frost, fog conditions works on the rock to expand and contract again and again, which results into the separation of the layer and the particles of the minerals. This complete process of known as weathering.

TYPES OF WEATHERING

1. PHYSICAL OR MECHANICAL WEATHERING : caused by the effects of changing temperature on rocks, causing the rock to break apart.

2. CHEMICAL WEATHERING : caused by rain water ( slightly acidic ) reacting with the mineral grains in rocks to form new minerals ( clays ) and soluble salts.

3. BIOLOGICAL WEATHERING : caused by Men, Animals, Insects and Vegetation.

EROSION

Erosion is the displacement of weathered rock from one place to another. It is a process by which soil and rock particles are worn away and moved elsewhere by gravity, or by a moving transport agent like wind, water or ice.

AGENTS OF EROSION

1. GRAVITY : down-slope movement of loose rock and soil due to gravity.

2. WIND : wind takes away dry and light sand particles from one place to another.

3. WATER : transports millions of tonnes of sediment everyday, along rivers, coasts, and even in the deep oceans.

4. ICE : movement of ice downhill causes erosion of underlying rocks.

HOW IS EROSION DIFFERENT TO WEATHERING ?

Erosion involves removal of solid material by a transporting agent. Weathering is the breakdown of rock into fragments at the Earth’s surface. Note : No movement is involved in weathering.