Deposition Geology: Definition, Examples, and Facts

Due to the continuous pressure/force of wind or water on the Earth's surface, erosion occurs in the Earth's surface.

Some natural phenomena like wind and water are continuously applying their forces to the surface of Earth. As a result, the Earth’s surface is eroded. Both of the natural phenomena particularly water transports this eroded material to some other location on the Earth and deposit it there. This action of natural agents is called deposition.

Let me explain deposition with an example. When it is raining, the ocean waves thrash against a rock and erode it. The eroded pieces of the rock, sand or dirt taken by the ocean waves to some other location and they are deposited in the air or on the ground. So, this process is known as a deposition. So, the process of deposition consists of two phases. In the first phase, the natural agents like water or wind erode the rocks. In the second phase, they carry the eroded pieces of rocks to some other places and deposit them into the air or water.

Deposition by water and wind


Agents Participating in Deposition

There are four agents that participate in the process of deposition. They are as below:

Frozen rivers/glaciers: They get the eroded material into them and transfer to some other location as they slide from an actual place.

Gravity: It interfere with the erosion when the rocks fall due to the earthquake.

Wind: It plays its part to carry the lighter material with it such as sand or dust particles and drops them away where it ends blowing.

Water: It works with all powers in different forms. The water in rivers and streams take up the sediment particles with it. In the form of floods, it carries heavier sediments with it to different locations. In the form of rainwater, it carries the sediments to various locations and deposits them.

Elements Affecting Deposition

There are several elements that affect the process of deposition after the erosion of rocks. Here they are:

Velocity: The speed of natural agents such as the velocity of wind or water plays a vital role in the process of deposition. If the velocity is lower, the heavier sediments cannot move with them. So, while carrying the eroded sediments, the velocity plays an important part. They drop the sediments where the velocity is lower and deposit them to that location.

Sediments’ Size: The size of the sediments, their thickness and volume also play a vital role in this process. If the eroded material is heavier, it will land first and the lighter particles deposit at a far off place due to their less density.

Sediment’s Shape: The shape of the eroded material plays an important role in the process of deposition. If the sediments are in round shape, they move quicker than the flat particles. In the same way, the sharpness of the eroded material takes them to more far off geographical locations.

Deposition Effects on Geographical Environment

Deposition affects the geographical environment in many ways. Following are them:

Gravity: It creates rock-sliding on the sides of the mountains and the rocks are deposited at the bottom.

Weight: The weight of the eroded material also creates rockslides.

Wind: Wind creates different sand dune patterns in deserts while taking the sand with it.

Rivers: When the rivers deposit sand and other eroded material with them, they create deltas. So, the water speed slows while reaching to deltas to be a part of the ocean.

Ocean Waves: The ocean waves with a forceful power create beaches and sand bars by continuously depositing sand to a particular location.

New Beaches due to deposition


Positive Effects of Deposition

Deposition affects the surface of the earth in a positive way somehow. In this context, let me give an example of the river Nile in the ancient times. The river Nile in Egypt affected the human civilization positively. Every year the Egyptians could see the Nile is flooded. As a result, it brought silt from the nearby lands located at its banks. Due to this fertile soil, the farmers were able to grow a large number of crops. So, the process of deposition brought prosperity and fertile lands in ancient Egypt.

The erosion and deposition form new islands. When the wind, water, and rain keep participating in the process of deposition to a particular location, it forms new islands. The silts and small pieces of rocks carried by the water are thrown on particular areas and thus, they form new islands.

When the ocean waves carry the silt and sand particles with them to a particular location, it forms new beaches. In this context, you can consider the Mar del Plata beach, Buenos Aires, Argentina. You can also take an example of the Paradise Island Beach, Bahamas.

Due to the deposition of alluvial sediments, the water bodies form deltas. River Nile also formed a delta due to the deposited alluvial sediments towards the Mediterranean Sea. Mississippi River also formed the Mississippi Delta in the US.

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