What type of erosion causes caves

This means that any material being carried by the sea is washed up and begins to build up along the coastline. The material that is deposited by constructive waves can most often be seen by the creation of beaches.

Image credit: Jeff Hansen, U. Geological Survey. Hydraulic Action Hydraulic Action is the sheer force of water crashing against the coastline causing material to be dislodged and carried away by the sea. Compression Compression occurs in rocky areas when air enters into crack in rock. This air is trapped in cracks by the rising tide, as waves crash against the rock the air inside the crack is rapidly compressed and decompressed causing cracks to spread and pieces of rock to break off.

Compression is one of the main processes that result in the creation of caves. Abrasion Abrasion is when rocks and other materials carried by the sea are picked up by strong waves and thrown against the coastline causing more material to be broken off and carried away by the sea. Attrition Attrition is when material such as rocks and stones carried by waves hit and knock against each other wearing them down.

As these materials are worn down sand and rounded beach pebbles are formed. Cliffs Sea cliffs are one of the clearest examples of sea erosion that we can see.

Sea cliffs are steep faces of rock and soil that are formed by destructive waves. Waves crashing against the coastline erode until a notch is formed. View the coasts menu. Landforms of erosion There is a range of landforms of erosion found along the coast. Headlands and bays Headlands and bays most commonly form along discordant coastlines.

A cave at Selwicks Bay, Flamborough. A sea arch at Selwicks Bay, Flamborough. Stack at Selwicks Bay Flamborough. A geo at Flamborough A geo formed behind an arch at Flamborough. Search for:. Drainage Basin Hydrological System. Coastal Landforms of Deposition. Landforms of Erosion. Storm Desmond Case Study.

Marine Processes. Sub-Aerial Processes. Over time, the cave will be eroded into an arch, accessible to the sea on both sides.

Weathering will also play a role, with physical weathering processes such as freeze thaw and salt crystallisation and chemical processes such as carbonation weakening the rock surrounding the cave or arch making it more susceptible to mass movement and collapse. Finally, the erosion and weathering continues and the arch collapses leaving behind a stack a vertical column of rock. These stacks can be attacked further, and eventually the stack may collapse to leave a low l ying stump.

Back to the top of the page. Coves form where rock runs in bands horizontal to the direction of wave attack. There is a band of resistant rock closest to the sea and a band of less resistant rock inland. Wave processes erode the softer rock faster and this leaves a circular cove with a narrow entrance where the sea enters.

The waves are also refracted within the cove, spreading out to erode in all directions. A good example of this is Lulworth cove. Bays and headlands. In areas where the geology or rock type runs at right angles to the coastline, bays and headlands can be created.

If there are alternating bands of harder and softer rock running at right angles to the sea, the sea will erode these bands at different rates called differential erosion. Hydraulic action, abrasion and corrosion are more effective at eroding the softer rock, particularly during storms, and this will erode further inland than the harder rock.

During calmer weather and no stormy periods, the hard rock will absorb a lot of the wave energy and refract or bend the waves into the area with the softer rock, allowing sediment to be deposited and accumulate as beaches.

The net result of this over long periods of time is that the hard rock is left jutting out to sea as a headland, and the softer rock is eroded into curved sand filled bays. Cliffs and cliff retreat A cliff is a vertical, near vertical or sloping wall of rock or sediment that borders the sea. They generally differ in their angle of slope because of their rock structure and geology, but the processes involved in their formation are the same.

Marine erosion processes attack the foot of the cliff and cause the erosion at a wave cut notch.