WHAT IS WEATHERING? CHARACTERISTICS AND TYPES - ENVIRONMENT - 2025

The weathering is the disintegration or alteration of the rock in its natural state or natural position through physical, chemical or biological. These processes are induced or modified by air, water or climate.

During weathering processes, the movement of disintegrated or altered material occurs in the immediate vicinity of the rock exposure, but the rock mass remains in place.

Weathering differs from erosion in that erosion usually includes the transport of disintegrated rock and soil away from the site where degradation occurred.

However, a broader application of weathering at or near the Earth's surface is also distinguished from the physical and chemical alteration of rock through metamorphism.

Metamorphism usually takes place very deep in the earth's crust at much higher temperatures.

Main characteristics of weathering

Weathering is the process by which rock dissolves, wearing away or breaking into smaller pieces.

Rocks, minerals, and soil normally change their structure under the influence of certain forces in the environment. Biological activity, ice, and wind cause rock and soil to wear away.

There are mechanical, chemical and organic weathering processes, depending on the type of agent that causes it.

Once the rock has been weakened and fragmented by weathering, it is ready for erosion. Erosion happens when rocks and sediments are picked up and moved elsewhere by ice, water, wind, or gravity.

Types

Different factors control the type of weathering and the frequency in which the rock goes through this process. The mineral composition of the rock determines the degree of alteration or disintegration. The texture of the rock also affects the type of weathering that is likely to affect it.

For example, fine rock is more susceptible to chemical alteration, but less susceptible to physical degradation. The pattern of fractures and fissures within the rock can provide the perfect opportunity for water to penetrate.

As a result, fractured rock masses are more likely to weather more than monolithic structures.

Climate also controls the type and degree of weathering by affecting the likelihood of freeze-thaw cycles and chemical reactions. Chemical weathering is more likely to occur - and to be most effective - in tropical and humid climates.

Mechanical weathering

Mechanical weathering or physical weathering breaks the rock physically. It is the physical disintegration of rocks into small pieces.

One of the most common actions of this type of weathering is the action of freezing or shelling of frost. The water gets into the cracks in the bedrock. When the water freezes, it expands and the cracks open up a bit more.

Over time pieces of rock fall off the rock face and boulders break into smaller rocks and gravel. This process can also break brick in buildings.

Another type of physical weathering is salt wedges. Wind, waves, and rain can also have an effect on rocks, as they are physical forces that wear down rock particles, particularly over long periods of time.

These forces are categorized as mechanical weathering because they release their pressure on rocks directly and indirectly, causing the rocks to fracture.

This weathering is also caused by thermal stress, which is the effect of contraction and expansion in rocks caused by changes in temperature. Due to expansion and contraction, rocks break into small pieces.

Organic / biological weathering

This organic weathering refers to the disintegration of rocks as a result of the action of living organisms.

Trees and other plants can wear down rocks as they penetrate into the ground, and as their roots get larger more pressure is placed on the rocks causing the cracks to open wider and wider.

Eventually the plants completely break the stones. Some plants also grow inside cracks in rocks, leading to the cracks getting larger and disintegrating in the future.

Microscopic organisms such as algae, mold, lichens, and bacteria can grow on the surface of rocks and produce chemicals that have the potential to break down the outermost layer of the rock; they eat the surface of the rock.

These microscopic organisms also bring in moist chemical microenvironments that encourage breakdown of the rock surface.

The amount of biological activity depends on how much life exists in that area. Burrowing animals like squirrels, mice, or rabbits can accelerate the development of fissures.

Chemical weathering

This kind of weathering occurs when rocks are worn down by chemical changes. Natural chemical reactions within rocks change the composition of rocks over time.

Because the chemical processes are gradual and continuous, the mineralogy of rocks changes over time causing them to dissolve and disintegrate.

Chemical transformations occur when water and oxygen interact with minerals within rocks to create different chemical reactions and compounds through processes such as hydrolysis and oxidation.

As a result, in the process of the formation of new materials, pores and fissures are created in the rocks, increasing the forces of disintegration.

Sometimes rain can also turn into acid rain when it mixes with acidic depositions in the atmosphere.

Acidic deposits are created in the atmosphere as a consequence of the combustion of fossil fuels that release nitrogen oxide, sulfur and carbon.

Acidic water resulting from precipitation (acid rain) reacts with mineral particles in the rock, producing new minerals and salts that can easily dissolve or disintegrate the grains of the rock.

Chemical weathering depends mainly on the type of rock and the temperature. For example, limestone is more prone to this than granite. Higher temperatures increase the rate of chemical weathering.

References

1. Weathering and erosion. Recovered from onegeology.org
2. Weathering. Recovered from britannica.com
3. What is weathering? Recovered from eartheclipse.com
4. Weathering. Recovered from nationalgeographic.org
5. What is weathering? Recovered from imnh.isu.edu