What Is Weathering - Understanding Process and Types
So, what is weathering?
In general, weathering is defined as the process of breaking down rock masses by exogenous forces. According to Ollier in his study that happened in 1963, weathering is the process of adjusting the chemical, mineral, and physical properties of rocks to the surrounding environmental conditions.
There are several factors that may cause weathering types, such as:
The Affecting Factors
After understanding the meaning of weathering, let us talk about the factors that may affect the weathering process.
The Types of Rock
Types of rocks consist of mineral content, fractures, layers, faults, and fractures, causing variations in the level of resistance to external influences. Resistant rocks are slower exposed to external processes, so they are not easily weathered. On the other hand, non-resistant rocks are more susceptible to resistance processes, so they are easily weathered.
Examples:
Limestone is resistant to dry climates but not resistant to wet climates.
Granite is resistant to wet climates but not resistant to dry climates.
Climate
The next factor here is climate, especially temperature and rainfall that will affect the level of weathering on particular rocks.
Example:
Dry climate, type of weathering = mechanical/physical
Wet climate, type of weathering = chemical
Cold climate, type of weathering = mechanical
Vegetation
The plantations or vegetations will slow down mechanical weathering. Vegetation is a supplier of organic acids and CO2 into the soil so that it will accelerate chemical weathering.
Topography
With a large slope and facing the direction of the sun/rain, this condition will accelerate the weathering process.
The Types of Weathering
After learning about what is weathering, let us discuss the types of weathering.
Earlier, we explained that weathering is the destruction of rocks on the earth's crust due to the influence of weather (temperature, rainfall, humidity, or wind). Therefore, weathering is the destruction of rock from the form of lumps into smaller grains, even being crushed or dissolved in water.
Weathering is divided into three types, namely mechanical weathering, chemical weathering, and biological weathering.
Mechanical Weathering
Mechanical weathering or often called physical weathering, is the physical destruction of rock without any chemical factors involved. The weather may be caused by freezing of water, expansion of the area, sudden changes in temperature, or the much difference of temperature between night and day.
In short, mechanical weathering is caused by these common factors:
- Due to land expansion
- Due to Freezing of Water
- Due to sudden changes in temperature
, d. Huge Temperature Difference between Day and Night
Chemical Weathering
Chemical weathering is a type of weathering that occurs as a result of chemical events. Usually, the medium here is water, especially rainwater. Did you know that rainwater or groundwater, in addition to H2O compounds, also contains CO2 from the air?
Therefore, it also contains energy to dissolve larger stones, especially if the water hits limestone or karst.
Limestone is easily dissolved by rainwater. Therefore, if you look at the surface of the limestone, there are always cracks in an irregular direction. The results of chemical weathering in karst areas usually produce underground rivers, stalactites, limestone pillars, stalagmites, or limestone caves.
Biological Weathering
Maybe you've seen people breaking rocks. The large stone was pounded with a hammer into small pebbles, which were used for building materials.
Or maybe, you've seen birds or other animals make nests on rocks, and over time, the rock becomes weathered. These two illustrations are examples of biological weathering.
Biological weathering or also called organic weathering occurs due to organic processes. The main factor here is a living being, either plants, animals, or humans. Plant roots grow in length and can penetrate and destroy rocks because roots are able to grip them.