Weathering of rocks

Weathering of Rocks, Types of Weathering, Cause of Weathering, Main difference between Weathering and Erosion

Weathering of rocks

Weathering of Rocks

Temperature, air, water, glacier etc. soften the badrock of the earth crust. After sometime the outer surface of the rock is covered by soft rock mixture. The process of forming soften rock mixture over a hard rock is called weathering. According to Spark, weathering is the mechanical fracturing and chemical decomposition of rock of the earth surface by the natural process.

Depending upon the process of weathering it can be divided into three parts-

1. Physical Weathering

2. Chemical Weathering

3. Biological Weathering

Physical weathering:

Physical weathering: Out all the two types of weathering that is disintegration and decomposition. The disintegration process is accomplished in nature by a greater variety of natural agencies like wind, water, glaciers, gravity, temperature, pressure etc. 

Wind: 

Wind is a relatively weak natural force inspite of which it can cause disintegration or create favourable condition for weathering.

Water: 

Water causes weathering of rocks in a form of natural water falling as rain drops Or aa hailstorm on the surface of rock or running water or dashing waves and tides of sea, accelerate weathering.

Glacier: 

During movement of glaciers, the rocks are eroded separately and finally broken into finer particles.

Change of temperature: 

The change of temperature works on the surface of the rocks. The rocks expand on heating in the daytime and contract on cooling in the night. The pressure developed on the rock due to continuous expansion and contraction the continuous change of temperature puts off thin layer of rocks. 

Frost action: 

In cold countries water in the day time enters into the cracks, hales in the rock. The water freezes in the night and it's volume increases. It crushes the rocks and weakened them.

Gravity:

 Many rocks which large joins disintegrates on account of gravity because of gravitational force. They were attracted towards centre, falls down and breaks in pieces. 

Chemical weathering:

Oxygen and carbon dioxide present in the atmosphere mixed with rain water works as a weak acid and reacts with mineral present in the earth surface or rock. 

Oxidation: 

The oxygen present in the atmosphere reacts with minerals in presence of water, because of this oxide irons present in the rocks changes from ferrous to ferric acid. 

Carbonation: 

Carbon dioxide present in the atmosphere mixed with rain water to form carbonic acid, which reacts with the hydroxide of soil forming minerals forms in soluble carbonates. Sometimes it dissolves minerals and thus weakens the rock thereby promoting weathering. 

Solution:

Solvent action of water helps in the weathering of rocks. It dissolves soluble minerals of rocks and the process disintegrate the rocks. 

Reduction:

Reduction takes in the zones, where the soil is rich decaying vegetation. It causes removal of oxygen from minerals.

Biological weathering:

Trees and plants, animals man and even bacteria helps in disintegration and decomposition of rocks.

Trees and plants: 

The developing roots of the trees enters cracks and joins of the rocks and loosen the rock from inside which accelerate the process of weathering. 

Animals: 

The major contribution towards contributing from animals and plants is that after death their soft parts decay and decompos releasing toxic products which brings about decomposition of rocks particularly reduction. Burrowing animals also accelerate weathering process.

Bacteria:

Some bacteria takes part in decomposition of rocks by decaying of organic material and producing humic carbonic and other acids.

Man:

Man ranks top in the list of various agents responsible for forces unnatural weathering of rocks. Rapid urbanization and industrialisation have resulted in rapid disintegration or degradation of hills and mountains thereby anchoring weathering of rocks. 

The main difference between Weathering and Erosion-

The main difference between weathering and erosion is that the loose material over the hard bedrock is called weathering and this loose material when transported away by different agents from one place to another is called erosion. During transportation also by way of usual friction. Some amount of disintegration takes place and this is called erosion.