Denudation
Denudation and Weathering is exogenic process. In denudation activity, the earth’s surface level is down or rock wastage occurs. When denudation occurs on large objects i.e. mountains etc. it is converted into a flat surface area.
weathering, erosion, transport, and mass movement, all happen in which process that process called denudation. And all this happens because of, water, wind, and ice (glaciers). After weathering starts the erosion process after the erosion process starts transportation after the transportation process starts deposition. (Endogenic and Exogenic Process)
Denudation Includes Three Processes,
1. Weathering
2. Mass wasting
3. Erosion
Weathering
Weathering can happen because of air and water. the upper layer of the Rock can be loose Because of air, water, and rain. Minerals of that rock also can separate, can detach, and the upper layer can be de-compose, this process is known as weathering. When soil deposits start to occur, weathering increases more in that soil. in Weathering process, does not change temperature. Weathering happens because of temperature, humidity, and precipitation. (Denudation and Weathering)
Regolith
Things that flow, do not flow completely, so the sediment that remains there, is called regolith. Regolith makes soil. Minerals in soil are due to regolith.
In Mechanical weathering
- Insolation
- Frost action
In Biological weathering
- Animal and insects
- Vegetation
- Human activities
Mass wasting involves
- Land sliding
- Mud sliding
- Soil creep
- Avalanche
In Chemical weathering
- Oxidation
- Hydration
- Carbonation
- Solution
Characteristics of Weathering in Denudation and Weathering
- When the process of Rock disintegrates, we called it weathering.
- In disintegration, the breaking down of the rock takes place.
- In disintegration, Rock breaks are not removed.
- Weathering is a good source of soil formation work.
- Weathering depends upon climate conditions.
- In dry climates mechanical weathering is common.
- Rock breaks down into small stones, small stones slowly transform into pebbles, and pebbles transform into fine particles, which are then transported from one place to another.
- The nature of the rock (texture, composition, and hardness) includes these things and determines the type of weathering that will or will not occur.
There are TWO types of weathering
1. Chemical Weathering
2. Physical and Mechanical Weathering
A. Mechanical Weathering
Mechanical weathering is also known as physical weathering. Rock is breaking down but its chemical composition does not change, this type of weathering is called mechanical weathering. The main causes of mechanical weatherings are moisture changes in temperature, frost action, and wind. This type of weathering occurs in desert areas because the temperature is high there.
There are FOUR types of mechanical weathering
1. Block Disintegration
When the temperature fluctuates, the rock begins to break down. Higher temperatures cause the particles to grow or spread. Low temperature causes the particles to shrink, this is called block disintegration.
2. Granular Disintegration
The agents of weathering disintegrate the rock, and it turns into small pieces that look like grains of wheat, so it is called granular disintegration.
3. Exfoliation
Sudden temperature changes can cause cracks in the rock, its top layer can peel off/ turn yellow. When water seeps into a rock, its top layer is moved away, it is called exfoliation.
4. Frost Action
Where there are dry climates, the rocks are filled with some kind of water, and because of the low temperature at night, the water freezes, and due to this, the water space starts increasing, and because this action happens every day, the rock breaks in one day.
B. Chemical Weathering
Two or more minerals are mixed in the rock, and the minerals that are in the rock change its characteristic and react, any organic acid and the rock starts to decompose due to that reaction is called chemical weathering. This happens because of a chemical reaction.
There are FOUR types of chemical weathering.
1. Solution
If the rock contains some minerals, which will react with water and mix with it, it is called a solution. How fast or how slow they mix depends on the chemical composition and the type of rock.
2. Carbonation
Some rocks contain carbon dioxide, and when carbon dioxide reacts with water, an acidic effect occurs, causing the rock to break down. Rainwater converts carbonate into calcium. Some rocks are like marble and limestone, and are dissolved in water,(Bicarbonate is soluble so it dissolves in water)
3. Oxidation
There are minerals in rock that react with oxygen. Rainwater also contains atmospheric oxygen. If there are iron compounds in the rock and they come in contact with rainwater, rusting starts at that time. This can also change the color of the rock (red, brown, yellow)
4. Hydration
If there are minerals in the rock, which are expanding after coming in contact with water, only then the process of hydration takes place, due to contact with water, they become heavy and start breaking. The rock is converted from feldspar to kaoline.
Differences between Chemical Weathering and Mechanical Weathering in Denudation and Weathering
| Chemical weathering | Mechanical weathering |
| There is no change in chemical composition, but there is a change in chemical composition | Rock disintegrates but its chemical composition does not change |
| It is found in hot and humid regions | They live where there is more heat |
| Here main agents are temperature, weathering, and moisture. | Rock has more effect and can have an effect up to a depth |
| It only affects the surface | Here main agents are, temperature, weathering, and moisture. |
C. Biological Weathering
This weathering is also called organic weathering. The main agents of this weathering are animals, insects, humans, plants, etc. The biological matter is made up of oxygen and water. And this causes a chemical reaction in the rock, resulting in corrosion and physical breakdown.
How does biological weathering occur?
- When a body is buried underground, as the body begins to decompose, it releases chemicals, and those chemicals begin to react with the composition, causing the rock to disintegrate.
- Vegetation
- Humans- humans are the most active agents of physical and chemical weathering.
e.g mining, construction of roads and buildings, agriculture, and dumping of chemicals.
Weathering Indifferent Climatic Regions
Chemical weathering occurs due to the hot and humid climate in the equatorial region because there is high temperature and humidity. In tropical regions, dry and wet seasons are distinct, and high temperatures increase evaporation. Where there is a cold climate, physical and mechanical weathering takes place because the temperature is very high during the day and the night is very cold, (Polar regions).
Mass Wasting
Mass wasting means that waste material goes from one place to another in large quantity, it is called a mass movement, this water and wind, and glaciers start moving downwards.
There are TWO types of mass wasting
1. Slow mass wasting
2. Rapid mass wasting
Slow mass wasting
When the rock starts to break down it is known as soil. If the rock does not break/weathering, if it starts to flow, it is called rock creep.
Rapid mass wasting
Landslide, fall slide, sheet wash, mudflow, earth flow.