Landforms Produced by Sea Waves Part 4

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Landforms Produced by Sea Waves

The tides, waves, and ocean currents contribute to the restlessness of the ocean. Their continuous effect on the coasts creates several relief features. The work of sea waves as an agent of gradation includes the processes of erosion, transportation, and deposition. Many topographical features are made through these actions of waves. Such features are found mainly in the coastal regions. Let us study the work of sea waves in details.

Erosion By Sea Waves: In their role of an erosional agent sea waves perform four functions. When the sea water loaded with rock fragments and sand, attack the coastal rocks, it is known as abrasion. When the rock particles present in the water hit against each other and break into progressively smaller particles, this process is known as attrition. The broadening of cracks and crevices in the cliffs along the coast due to the attack of the sea waves is known as hydraulic action. The rocks made up of limestone are mainly subjected to solution action by sea waves. These processes help in the formation of new features on the coastal margins.

Landforms Produced by Sea Wave Erosion

Waves erode the coastal rocks with the help of rock fragments present in the water. Due to the continued erosion by waves, the coastline keeps retreating and many topographical features are formed in this process. Some of the important features made through sea wave erosion are:

Sea Cliff: The maximum impact of the sea waves is observed on the lower part of the coastal rocks. Consequently, the lower part of the rocks eroded more rapidly than the upper part. This results in the formation of a hollow under the rock. With the passage of time this excavation in the lower part of the rock keeps on becoming larger.

The upper part of the rock is therefore left projecting out towards the sea. With time, this projecting part fall into the sea under its own weight. As a result, a vertical wall is left, known as a cliff. In India a number of sea cliffs are found along the Konkan Coast of India.

Sea Caves: Erosion is not uniform when the upper part of the coastal rock is hard and the lower part is soft. The lower part of the rock in such circumstances is eroded faster than the upper part. Due to the differential erosion a hollow is created in the lower part of the rock. When the waves pound against this hollow, the air present in the hollow gets compressed. When the wave comes out of the hollow, the pressure on the air is also released as it expands. Due to the continuous compression of the air in the hollow, the rocks are subjected to great pressure and they break. in this process, the hollows in the lower part of the rock keep on enlarging. With time they attain the form of caves, known as sea caves. Formation of caves depends upon the nature of the coastline and the force of the waves.

Geo and Blow Hole

Geo and Blow Hole

Geo and Blow Hole

Sea Arches: When a part of the coast extends to some distance into the sea, the sea waves working from opposite directions cut a passage through the soft rocks. In the initial stage, this passage is a narrow hole, but it enlarges into a broad arch. These broad doors like features are known as sea arches or natural bridges.

Sea Stacks: When the roof of an arch is broken by erosion or under its own weight, a part of the original rock remains standing as a solitary mass. It may be the rock, forming the side of the arch. This type of a feature is termed a sea stack. Stacks are of different types depending upon their shape and the nature of the rocks. Small underwater stacks are termed stumps.

Topographical Features Produced Due To Wave Erosion

Topographical Features Produced Due to Wave Erosion

Topographical Features Produced Due To Wave Erosion

Transportation by Sea Waves: Sea waves, currents, and tides are the chief agents of transportation of eroded material in the coastal regions. But, the role of waves is more important in connection with the formation of coastal relief features. The materials deposited on the coasts by the rivers and glaciers are removed and transported by the waves. Transportation by sea waves is mainly carried out in two ways:

  • Removal and transportation towards the sea of the material deposited by river on the coast.

  • Carrying of materials found in the sea to the coastal areas. During this process, the oceanic materials like pearls, and other shells are brought to the coast.

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