Weathering, Erosion, and Deposition

In this article we are going to learn about the weathering process. The weathering process is followed by two other phenomenons of erosion and deposition. Let's dive into it.

Weathering: 

The wear and tear/ breaking down and changing of rocks as a result of exposure to environment. weathering of rocks happens with the time. It can take hundred or thousand of years.

Types of weathering: 
On the basis of the environment and factors, weathering is divided into two key terms.

• Physical weathering  
• Chemical weathering

Let's look at each types of weathering in detail:

Physical/Mechanical weathering: This type of weathering does not change the chemical structure or composition of the rock but the shape of the rock. It is of four types:

1. Frost action
2. Exfoliation
3. Abrasion    
4. Root wedging

Here's a detailed table to understand each type of physical weathering which tells us how it happens, where it happens and what does it involves.

Details:	Frost action	Exfoliation	Abrasion	Root wedging
Happens where:	In areas temperature is slightly above freezing during day and below freezing in the night.	Dramatic temperature conditions, mostly in areas where temperature is very hot during the day and very cold during the night	Rock grinds against rock and results in abrasion	Plants roots force the rocks apart
Involves:	Ice process	Extreme temperatures	Air abrasion, water abrasion, glacial abrasion, coastal abrasion	Plants roots
Process:	Water seeps in the cracks of rocks and during night it freezes. When water freezes its volume increase. The result of this freezing and expanding of water	Rock expands during the day in heat and contracts during night in cold and gradually the outer layer of rock exfoliates	Air flows the sand into bigger rocks and it gradually becomes abrased Water flows little peebles or smaller rocks into larger rocks	Little plants grow under rocks and they grow to a large tree, their powerful roots tear apart the rocks

Chemical weathering: This type of weathering changes the chemical structure of rocks as a result to exposure to different substances and gives them a new name and shape. It is also divided into two main types.

• Oxidation
• Carbonation

Let's look at each type of chemical weathering individually.

Oxidation: The term is used to represent rust and involves the process of rocks turning red. The phenomenon behind the rocks turning red is the exposition of oxygen to air. As we know, many rocks over the world contain oxygen so whenever they are exposed to air they turn red and looks like rusted.

Carbonation: this process is responsible for many beautiful and eye catching limestone caves over the world. the process starts with the water seeping underground and mixing with different minerals to form carbonic acid. carbonic acid have the ability to dissolve many other minerals so it forms caves etc when the rocks are exposed to this carbonic acid.

Factors affecting weathering:

Climate:  If the temperature is moderate and least moist, very less weathering is seen but in higher temperature and dry areas, more and strong weathering is visible.

Surface area: The larger surface area provides more weathering process. This tells that a larger rocks whose center is protected or less surface area is less vulnerable to weathering while a smaller rock whose center is exposed more, provides more surface area for weathering. 

Hardness:  The hardness of different rocks also affects the weathering process. Some rocks are more prone to weathering due to their softness than other harder rocks.

The term weathering is often used with two other terms: erosion and deposition

Erosion: 
is the process of transportation of the broken rock sediment to far places. it is followed by deposition

Agents of erosion: As we know erosion is the process of transporting the broken rock far from its parent rock. the process of erosion is caused by many factors that include:

• Soil
• Air
• Water
• Ice 
• and the most important Gravity

Gravity is the most crucial factor of erosion process as it causes the factors work directly or indirectly. The erosion that takes place through gravity is called mass movement.

There are four types of erosion that take place through gravity.

1. Soil creep
2. Debris flow
3. Mud flow
4. Rock fall

Properties↓/Names→	Soil creep	Debris flow	Mud flow	Rock fall
Constitutes of:	Only soil	Everything including trees, rocks, soil, etc.	Only mud and water	Mainly rocks and take other things with it also
Time it take:	Can take weeks, months, years or decades	Sudden fall, can't be predicted	Mostly during rain, storms, heavy precipitation	Rapidly falls off the cliff
Also known as:	=	Landslide	Mudslide	Rockslide

Deposition:
 As the name suggests is the settlement of of the sediments of rocks that are broken as a part of weathering process and transported as the result of erosion.

The deposition of the broken rocks by gravity erosion will be angular (sharped, pieces of rocks) and unsorted (not a specified position).

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