Using examples, describe and explain how erosion results in the formation of two coastal landforms.

Coastal erosional landforms are commonly found in high energy environments, where large waves, strong winds and tidal currents drive erosion. There are a number of different mechanisms which cause erosion, including corrasion, hydraulic action, solution and attrition. One landform typical of coastal erosion are headlands and bays. Headlands and bays often form along discordant coastlines, where the geology alternates between bands of hard and soft rock. The softer rock is more susceptible to erosion and therefore erodes more rapidly, forming the bay, whilst the harder rock is resistant to erosion and therefore extends further into the sea. A good example of a headland and bay system is Swanage Bay, Dorset (insert diagram). In this example, wave energy causes erosion via corrasion, as waves have the energy to carry pebbles with force. Similarly, erosion is caused by hydraulic action, as the high energy waves impact on the coastline directly, loosening the interior of joints and bedding planes of the rocks causing the coastline to disintegrate. Other typical landforms of coastal erosion are arches, stacks and stumps. Sea cliffs often contain faults or joints, which are weak points in the cliff and are thus more prone to erosion. Erosion, caused by hydraulic action, corrasion, solution and attrition cause these faults to widen. If these faults widen sufficiently, a cave can form. Continued erosion can lead to widening and deepening of the cave, and eventually the cave can breach the other side of the headland, forming an arch. A good example of an arch is Durdle Door, Dorset. Due to the dynamic nature of coastal systems, the base of the arch is still subjected to erosion, which weakens the arch. Ultimately, this erosion can lead to the arch collapsing. This collapsing results in a column of rock separate from the mainland, this is known as a stack. Further erosion and weathering of the sea stack leads to the formation of a sea stump. A great example of a stack and stump is Old Harry and Old Harry’s Wife, Dorset. The following diagram shows the progression from a headland to a stump.