A river delta forms at the mouth of a river where it enters a larger body of water. Usually the delta is shaped like a triangle.
What process causes delta formation?
Responses
A the movement of the tidesthe movement of the tides
B erosion of the river bankerosion of the river bank
C wave actionwave action
D deposition of sediments
D - deposition of sediments causes delta formation. When a river meets a larger body of water like an ocean or a lake, the water slows down and drops its sediment load at the mouth of the river. Over time, these sediments build up and form a delta, which is often triangular in shape.
The correct answer is D, deposition of sediments. Here's how you can arrive at this answer:
Deltas are formed when a river carrying sediment reaches a larger body of water, such as an ocean or a sea. As the river enters the larger body of water, its speed decreases, causing it to lose energy. This decrease in energy leads to the deposition of the sediments it was carrying. Over time, these sediments accumulate and build up, forming a delta.
The other options, A, B, and C, are not the primary causes of delta formation:
A. The movement of tides refers to the rise and fall of ocean water due to the gravitational pull of the moon and sun. While tides can influence the dynamics of a delta, they are not the main cause of its formation.
B. Erosion of the river bank refers to the process of wearing away the riverbank due to the actions of the flowing water. While erosion can contribute to the supply of sediment, it doesn't directly cause delta formation.
C. Wave action refers to the movement of waves in the ocean, which can also influence the shape and erosion of deltas, but it is not the primary process responsible for their formation.
Therefore, the correct answer is D, deposition of sediments.