Geotourism and modern Geotechniques
The marine process is the form of a Geomorphic process where Sea waves act as Powerful agents for erosion transportation and deposition.
The waves originate due to the sweeping of winds over the water's surface and erode the material.
On approaching shallow water near the shores, the wave speed is reduced and they are curved and refracted against the alignment of the coast.
Type of marine erosion
Sea waves, aided by winds, currents, tides, and storms carry on the erosional and depositional processes. There are 4 types of erosion-
1. Corrasion or Abrasion- Rock debris of all sizes with sea Waves Grind against the base of the cliffs and wear them back by corrosion, the process is repeated on coming tides and waves (Backwash).
2. Attrition waves that transport the Rock materials such as boulders, pebbles, and fine sand, also hurl these materials against each other until they are broken into small pieces.
3. Hydraulic Action-Hydraulic action is the erosion that occurs when the motion of water against a rock on the surface produces mechanical weathering. Most generally, it is the ability to move water (flowing or waves) to spread and transport rock particles.
4. Solvent Action-The solvent or chemical action of waves is another mode of erosion, but it is pronounced only if soluble rocks like limestone and chalk are present. On limestone coasts, the solvent action of the seawater on calcium carbonate sets up chemical changes in the rocks and disintegration takes place.
Marine transportation
Solution- minerals are dissolved in the water and carried along in the solution.
Suspension-fine light material is carried along in the water.
Saltation-small pebbles and stones are bounced along the sea bed.
Traction-large boulders and rocks are rolled along the sea bed.
Marine deposition
Deposition occurs when energy levels decrease in environments such as bays and estuaries. Where deposition occurs on the inside of a spit a salt marsh can form.
Erosional marine landform
Headlands and Bays-Cliffs along the coastline do not erode at the same rate. When a stretch of coastline is formed from different types of rock, headlands and bays can form.
Cliffs and Wave Cut platforms- Cliffs are shaped through erosion and weathering. Soft rock erodes quickly and forms gentle sloping cliffs, whereas hard rock is more resistant and forms steep cliffs. A wave-cut platform is a wide gently sloping surface found at the foot of a cliff.
Caves, Arches, Stacks, and Stumps-Caves, arches, stacks and stumps are erosional features that are commonly found on a headland. Cracks are widened in the headland through the erosional processes of hydraulic action and abrasion. As the waves continue to grind away at the crack, it begins to open up to form a cave.
Chasms-These are narrow, deep indentations carved due to headwords erosion through vertical planes of weakness in the rocks by wave action.
Creek and Inlet-Creek is a natural stream of water normally smaller and often tributary to a river. A creek is a narrow, sheltered waterway, especially an inlet in a shoreline or channel in a marsh. Inlet is an indentation of a shoreline, usually long and narrow, such as a small bay or arm, that often leads to an enclosed body of salt water, such as a sound, bay, lagoon, or marsh.
Ria and Cove-A ria is a coastal inlet formed by the partial submergence of an unglaciated river valley. It is a drowned river valley that remains open to the sea.
A cove is a small bay or inlet with a sheltered or restricted entrance.
Depositional marine landform
When water loses its energy, any sediment it is carrying is deposited. The build-up of deposited sediment can form different features along the coast.
Beaches-Beaches are made up of eroded material that has been transported from elsewhere and then deposited by the sea.
Spits and Hook-A spit is an extended stretch of sand jutting out into the sea from the land. Spits occur when there is a change in the shape of the landscape or there is a river mouth.
Bars and Lagoons-Sometimes a spit can grow across a bay and join two headlands together. This landform is known as a bar. They can trap shallow lakes behind the bar, these are known as lagoons.
Tombolo's-A tombolo is a sandy isthmus. Sometimes, islands are connected with the mainland by a bar called a tombolo.
Marine Dunes-With the force of on-shore winds, a large amount of coastal sand is driven landwards forming extensive marine dunes.
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