Weathering Process - Its Types, Advantages, Disadvantages, Significance to Human Life And More

The weathering process is the natural dissolution or breaking down of rocks and minerals on the Earth’s surface, but it can be accelerated by human activity. Weathering occurs when a rock deteriorates due to biological, chemical, and physical processes. Weathering and erosion are caused by water, salt, acids, plants, animals, and temperature changes.

This topic of ‘Weathering Process’ is important from the perspective of the UPSC IAS Examination, which falls under General Studies Paper 1 (Mains) and General Studies Paper 1 (Preliminary) and particularly in the Geography section of UPSC IAS EXAM. In this article, we shall discuss the ‘Weathering Process’ and learn about Weathering Process Phenomena, Different Types of Weathering, Differences, Examples, & More!

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What is Weathering?

Weathering refers to the process of breaking down rocks, soils, and minerals on the Earth's surface. It is caused by various factors, such as exposure to air, water, temperature changes, and biological activity. Weathering can be categorized into two types: physical weathering and chemical weathering. Mechanical weathering involves the physical breakdown of rocks into smaller fragments without changing their chemical composition. Chemical weathering, on the other hand, involves the alteration of rocks and minerals through chemical reactions, leading to their decomposition and the formation of new substances. Weathering plays a crucial role in shaping the Earth's landscape over long periods of time. It is an important part of the rock cycle and contributes to the formation of soils. 

Process of Weathering

Weathering is the process by which rock breaks down as a result of physical, chemical, and biological stresses.

• Temperature and moisture (climate) both affected rocks.
• When rocks disintegrate, more surface area is exposed, making them more susceptible to further physical, chemical, and biological weathering.
• Minerals that were once bound in the rock structure are released during weathering.
• The level of weathering that occurs is determined by the interaction of temperature and rainfall on physical weathering and chemical weathering processes.
• The weathering process is usually limited to the top few meters of geological material because physical, chemical, and biological stresses decrease with depth.

https://blogmedia.testbook.com/blog/wp-content/uploads/2022/06/weathering_2-f47aa5b7.png Process of Weathering 

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Different Types of Weathering

The process of breaking down rocks into sediments, clays, soils, and substances that dissolve in water is known as weathering and occurs at the Earth’s surface.

The process of creating soil begins with weathering. There are 4 ways in which weathering can occur:

• Chemical weathering
• Physical or Mechanical weathering
• Biological weathering

Chemical Weathering

Chemical weathering occurs when minerals in rocks undergo alterations through interactions with mineral solutions, leading to changes in the rock's composition. This process is triggered by chemical reactions that render the minerals unstable upon exposure to surface conditions. The specific transformations that take place depend on the particular mineral involved and the surrounding environment.

There are several types of chemical weathering, but the following are the most significant:

• Carbonation
• Hydrolysis
• Oxidation
• Hydration

Carbonation

Carbonation is the reaction of rock minerals with carbonic acid. Water and carbon dioxide react to form a weak acid, carbonic acid. In particular, limestone and chalk rock minerals are broken down or dissolved by carbonic acid.

• Carbonate rocks are sedimentary rocks that are primarily composed of carbonate minerals.
• Carbonic acid can easily dissolve limestone.
• The two major types are limestone minerals, including:

• Calcite or Aragonite
• Dolomite or Dolostone

Hydrolysis

The breakdown of rock by acidic water to produce clay and soluble salts is known as hydrolysis.

• For example, Sodium minerals combine with water to form a saltwater solution in many rocks.

• This type of chemical reaction occurs frequently in igneous rocks.

Oxidation 

Oxidation is a type of chemical weathering. Rusting is another name for oxidation. It is the process by which rock minerals lose one or more ions or atoms when oxygen is present.

• It occurs when free oxygen ions combine with iron and magnesium-rich minerals to form new minerals such as hematite and limonite.
• The minerals that are most prone to oxidation are pyrite, olivine, magnetite, amphibole, pyrite, and pyroxene.
• The expansion of rust causes a weakening and softening of rock.

Hydration 

Hydration weathering is a type of chemical weathering that occurs when a mineral interacts with water and changes its chemical bonds.

Hydration occurs when the mineral anhydrite reacts with groundwater.

Gypsum, one of the most prevalent minerals on Earth, is created when water reacts with anhydrite.

Physical Weathering

Physical weathering, also referred to as mechanical weathering, is a process devoid of chemical reactions that takes place as a result of temperature fluctuations, leading to the fragmentation and disintegration of rocks, minerals, and soils. Water, in both its liquid and solid forms, often acts as a prominent agent of mechanical weathering. This type of weathering is most commonly observed in regions with sparse vegetation and limited soil, such as high mountains and arid deserts.

Physical weathering can be classified into 4 types:

• Freeze-Thaw Weathering or Frost Wedging
• Exfoliation Weathering or Unloading Due to Thermal Stress
• Salt Weathering or Haloclasty
• Honeycomb weathering

Freeze-Thaw Weathering or Frost Wedging

Water seeps into cracks, freezes, and expands, eventually breaking the rock.

• During the warm and monsoon seasons, water penetrates the pore spaces or fractures in rocks.
• During the cold season, the water freezes and expands in volume.

• The ice then functions as a wedge.
• It gradually enlarges the cracks and splits the rock.
• Freeze-thaw weathering of rocks, also known as cryofracturing.

Exfoliation Weathering or Unloading due to thermal stress

This type of weathering occurs when cracks form parallel to the land surface. As a result, a reduction in pressure occurs during uplift and erosion.

• Temperature variation is known as thermal stress, which contributes to mechanical weathering.
• Temperature changes cause a rock to expand during hot weather and contract during cold weather.
• As this occurs repeatedly, the rock’s structure weakens. It deteriorates over time.
• The outer layer of desert rocks experiences repeated pressure as the temperature changes from day to night.
• Thermal stress is especially damaging in rocky desert landscapes.

Salt Weathering or Haloclasty

Salt weathering is a geomorphic process that causes the physical breakdown of rocks or stones as well as surface cracking.

• Haloclasty is the salt-induced weathering of rock.
• Saltwater can get into rock cracks and pores.
• When saltwater evaporates, salt crystals are left behind in the rock.
• As the crystals grow, they exert pressure on the rock, gradually breaking it apart.
• Haloclasty is not restricted to coastal environments.
• The honeycombed stones in sea walls are an example of salt weathering.

Honeycomb weathering

Honeycomb weathering is a common surface phenomenon that affects numerous different types of rocks in many different environments.

• Honeycomb weathering forms large networks of small cavities on rock surfaces.
• These patterns begin as a series of shallow depressions, but as they progress, they form deep chambers separated by thin septa of unweathered rock.
• Honeycomb weathering is linked to haloclasty.
• Honeycomb weathering is common along coastlines, where sea sprays force rocks to interact with salts on a regular basis.

Biological weathering

Biological weathering refers to the process in which rocks are weakened and disintegrated by living organisms, such as plants, animals, and microbes. Plants, animals, and microbes all possess the capability to serve as agents of biological weathering. In rock cracks, tree seeds can germinate and grow, causing the cracks to widen as the roots expand, eventually breaking the rock into fragments. Even large rocks can be fragmented over time by the actions of trees. Even the tiniest organisms, such as bacteria, algae, and lichens, release chemicals that aid in the breakdown of the rock they inhabit as they extract necessary nutrients. Numerous small animals burrow into rocks for protection, either by abrasively removing grains or by secreting acid to dissolve the rock.

Learn more about the Types Of Rocks!

Difference between Mechanical weathering and Chemical weathering

Here are some key differences between the mechanical and chemical weathering of rocks:

Difference between Mechanical and Chemical Weathering
Mechanical Weathering	Chemical Weathering
Mechanical weathering occurs when rocks disintegrate without changing their chemical composition.	Chemical weathering occurs when the minerals in the rocks dissolve, causing a change in the chemical composition of the rocks.
Thus, Mechanical weathering has no effect on chemical composition.	Thus, The chemical composition changes during chemical weathering.
Mechanical weathering occurs in regions of extremely hot and dry climatic conditions, where the temperature varies during the day and night.	Chemical weathering occurs in hot and humid climates.
The primary driving forces behind mechanical weathering are temperature, winds, moisture, and flowing water.	The primary agents of chemical weathering are oxidation, solution, carbonation, and hydration.
Mechanical weathering affects rocks at great depths.	Chemical weathering occurs primarily near the Earth’s surface.
Frost and salt wedging, unloading and exfoliation, water and wind abrasion, impacts, and collisions are all examples of mechanical weathering.	Carbonation, oxidation, hydration, and hydrolysis are examples of chemical weathering.

Learn more about The Rock Cycle!

Pros and Cons of Weathering

Here are some weathering process advantages and disadvantages below in the table:

Weathering Process Pros and Cons
Pros	Cons
Exposed rock surfaces are a source of soil and soil nutrients.	Chemical weathering also leads to oxidation, which is responsible for rusting.
Without weathering, the composition of the same valuable material may be insufficient to extract, process, and refine.	Natural disasters such as rockslides and mudslides, which kill hundreds of people each year, can be caused by the weathering process.
The warmer climate raises chemical weathering, which consumes Co2 from the atmosphere and mitigates the greenhouse effect, thus leading to climate cooling.	Weathering and erosion can alter the shape, size, and texture of various landforms.
Enhanced weathering causes the water to become more alkaline, which can help to mitigate ocean acidification.	The weathering process allows for a type of gravity erosion known as mass wasting by breaking rock apart into smaller pieces. It has the ability to destroy man-made structures and even kill.

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Importance of Weathering to Human Life

The weathering process is an important process because it breaks down rocks and minerals, which helps in the formation of soil.

• Weathering also helps to enrich the soil.
• Soil is required for plant growth, which provides food and oxygen to animals and humans.
• Weathering is responsible for the formation of landforms such as mountains, valleys, canyons, and plateaus.
• Weathering generates other natural resources, such as clay, which is used to make bricks.

What human activities can speed up the weathering process?

Humans can influence the rate of weathering in the following ways:

• Humans contribute to an increase in acidic pollutants in the atmosphere.
• When conventional fuels like coal and petroleum are burned, they emit nitrogen oxide and sulphur dioxide, both of which contribute to acid rain.
• Thus, the chemical weathering process is accelerated by acid rain.

Learn more about Landforms Created By River!

How is weathering different from erosion?

Here are some key differences between the weathering and erosion:

How is weathering different from erosion
Weathering	Erosion
Weathering is described as the decomposition of rocks, soil, and minerals due to direct contact with the atmosphere.	Erosion is described as the displacement of solids by air, water, ice, and gravity.
Weathering is a static process.	Erosion is a dynamic process.
Weathering occurs in a shorter time frame.	Erosion takes a longer time to complete.
The weathering process plays an important role in soil formation.	Erosion is a destructive process.
Mechanical, chemical, and biological processes can all lead to weathering.	Water erosion, wind erosion, snow erosion, and anthropogenic erosion are all types of erosion.

Learn more about Glacial Erosional Landforms!

Conclusion

The weathering process concludes that it is primarily caused by a natural process that results in the “disintegration of rocks,” which forms the components that lead to the formation of soil through the addition of essential elements to the topsoil.

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Previous Year UPSC Questions

Q1. The troposphere is a very significant atmosphere layer that determines weather processes. How? (UPSC Mains 2022, GS Paper 1).

Q2. Differentiate the causes of landslides in the Himalayan region and the Western Ghats. (UPSC Mains 2021, GS Paper 1).

Q3. The Himalayas are highly prone to landslides.” Discuss the causes and suggest suitable measures of mitigation. (UPSC Mains 2016, GS Paper 1).

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