Waves can pound this area causing fragments to break off, and the water can also trap air in pore spaces, faults and crevices, compressing the air which in turn exerts pressure on the rock causing it to break off. This process is known as. Another process that occurs is , where sediment and rocks in the sea water are hurled against the cliff face. All three of these processes erode the wave cut notch at the base of the cliff undermining the whole structure of the 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. The cave becomes larger and eventually breaks through the headland to form an arch. The base of the arch continually becomes wider through further erosion, until its roof becomes too heavy and collapses into the sea. This leaves a stack an isolated column of rock.
The stack is undercut at the base until it collapses to form a stump. 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. The erosion of this notch undercuts the ground above it until it becomes unstable and collapses. This process repeats itself and the sea cliff will continue to retreat.
Overtime a wave-cut platform will be formed in the sea just beneath the cliffs. This wave-cut platform will form at the low-tide level and is evidence of where the cliff face once stood before erosion caused the cliff face to retreat. Sea Caves Sea Caves form when cracks in rock at the base of cliffs are eroded and expanded by the sea.
The processes of compression and hydraulic are key to the creation of sea caves. Sea Arch Sea Arches are formed when a cave continues to be eroded and expanded until it cuts right through a headland.
Sea Stack A sea Stack forms when a sea arch continues to be eroded and widened until the rock becomes too weak to support the roof of the sea arch and collapses into the sea.
For example, erosion along some tidal creeks and dredged channels is caused by bank failure that forms small slump blocks Ginsburg and Perillo, The channels widen as the slump blocks are removed by tidal currents or by ice flowing through the channels. Physical Agents of Land Loss:. Sediment Budget. Relative Sea Level. Role of Shoreline Characteristics:. Role of Human Activities:.
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