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Weathering | Definition, its types

What is chemical weathering? Before we start a discussion on chemical weathering first learn about weathering.

What is weathering?

It is a physical and chemical process. Weathering is a change in the minerals of rocks and also physical alternation.


In simple words, it is the physical and chemical decomposition of rocks.


Example :

Oxidation, Freeze-Thaw, hydrolysis, etc.

Types of weathering :

Weathering is divided into three main types on the basis of the way of decomposition.

  1. Physical weathering
  2. Biological weathering
  3. Chemical weathering

What is Physical weathering?

It is the phenomenon of the decay of rocks. In physical weathering composition of minerals remain the same after weathering. In other words, physical weathering is the process in which there is a reduction in the size of rocks without alternation in chemical composition.

Example :

Sometimes water enters the rock and due to low temperature water freeze there. As ice occupies 9% more space than liquids. On melting of ice water flow out and cracks left behind this is an example of physical weathering.

Frost wedging

What is Biological weathering?

As it is clear from the name biological weathering. In such type of weathering. The decay of the rocks is due to some kind of living organism. It occurs by both means chemically and physically. It is generally simple breaking and movement.

Example :

  • Lichens /Algae are responsible for weathering.
  • When roots of plants made their way in rocks this is also a biological weathering.

What is chemical weathering?

This type of weathering is all about change in the chemical nature or chemically destruction of rock minerals. Chemical weathering is mostly done by rainwater. Rainwater in contact with rock minerals form new minerals or destroy them. Chemical weathering due to acidic rainwater is more rapid than neutral one.

Conditions for chemical weathering :

  • The rate of chemical weathering is higher under damp climates.
  • At higher temperatures rate of weathering is high.
  • Weathering process needs water.

Types of chemical weathering :

  1. Oxidation
  2. Hydrolysis
  3. Carbonation

Chemical weathering due to oxidation :

In such type of weathering rick minerals react with oxygen and there is a change in chemical composition also. Pure minerals also show resistance to weathering. When minerals react with the oxygen they oxidize and their resistance against weathering decreases.

Example :

Rusting of iron: In this phenomenon, iron reacts with oxygen and form rust on the surface.

Iron  +  oxygen  à  Rusting on iron surface

Chemical weathering due to hydrolysis :

In this type of weathering, there is an interaction between minerals and water. Slightly acidic water when reacting with minerals they produce new minerals due to chemical alternation. Due to acidic water rocks are breakdown and produce salts and clay.

Example :

Clay formation: in the process of clay formation Feldspar which is the most abundantly exciting mineral on earth reacts with carbonic acid which is a product of the reaction between water and carbon dioxide they form clay.

Feldspar +  Carbonic acid  a  Clay


Carbonic acid =  water + Carbon dioxide à Clay

Carbonation weathering :

It is the interaction of minerals with carbonic acid.

Carbonic acid =  water + Carbon dioxide à Clay

Example :

Cave formation is also an example of carbonation. Dissolve in limestone calcite they left open space.

Weathering produces soil :

As a result of physical and chemical weathering soil produces.

  • The area where the temperature is low and low rainfall physical weathering dominate there.
  • In the area where the temperature is high and high rainfall chemical weathering dominates there.

What is soil?

Soil is the uppermost surface of the earth with small rock particles that hold up plants.

What is Erosion?

Erosion is the loss of land or weathered particles by wind, air, and water.

Erosion due to water :

The movement of particles is because of water as like when soil loses vegetation, flooding, and many more.

Erosion due to the wind :

Wind also has an impact on soil. It has a devastating impact on dry soil.  As the wind blows away particles of dry soil and causes erosion.

Soil erosion

Bilal kamboh

A pioneer in the Chemistry space, Bilal is the Content writer at UO Chemists. Driven by a mission to Success, Bilal is best known for inspiring speaking skills to the passion for delivering his best. He loves running and taking fitness classes, and he is doing strength training also loves outings.

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