WEATHERING
WHAT IS WEATHERING?
- It is the breaking down or dissolving of rocks and minerals on Earth’s surface.
- Once a rock has been broken down, a process called erosion transports the bits of rock and minerals away.
- Water, acids, salt, plants, animals and changes in temperature are all agents of weathering and erosion.
TYPES OF WEATHERING
3 Types:
- Physical Weathering
- Chemical Weathering
- Biological Weathering
PHYSICAL WEATHERING
- It means mechanical disintegration of rocks due to changes in temperature by various cycles:
- Freeze-thaw
- Wet-dry cycles
- Salts crystallization
- Animal, plant and microbes’ activity
Processes of Physical Weathering:
-
- Exfoliation due to thermal stress and pressure release
- Frost weathering
- Granular Disintegration
- Salt Weathering
- Mass Wasting
- Honeycomb weathering
CHEMICAL WEATHERING
- It means chemical decomposition of rocks and soil.
- It changes the molecular structure of rocks and soil.
- It includes:
- Dissolution
- Carbonation
- Hydration
- Hydrolysis
- Oxidation
- Reduction that decomposes rocks into a fine state.
BIOLOGICAL WEATHERING
- It includes the removal of minerals from the environment due to growth, or activity of organisms.
- The seed of a plant may sprout in soil that got trapped in a cracked rock.
- Burrowing and wedging by creatures like earthworms, rodents etc. help in exposing the new surfaces for chemical attacks.
- Decaying matter of plants and animals help in the production of humus, carbonic and other acids.
- It further helps in decay and solubility of some elements.
- Some bacteria or algae can weather rock to get access of nutrients such as magnesium or potassium for its growth.