Erosional landforms
The process of erosionThe wearing away of pieces of rock, soil or other solid materials. can create different large scale landforms along the coastline.
Headlands and bays
cliffA vertical rock face. along the coastline do not erode at the same pace. A cliff is a steep rock face. When a stretch of coastline is formed from different types of rock, headlands and bays can form.
Bands of soft rock such as clay and sand are weaker, therefore can be eroded quickly. This process forms bayA low-lying inlet of land on the coast.. A bay is an inlet of the sea where the land curves inwards, usually with a beach. Hard rock such as chalk is more resistant to the processes of erosion. When the softer rock is eroded inwards, the hard rock sticks out into the sea, forming a headlandA high area of land that extends out into the sea.. An example of this is Saundersfoot Bay in Pembrokeshire, and Worms Head in Gower, Swansea.
Erosional features such as wave-cut platformA flat area in front of a cliff, just below the low tide mark. These were formed when the waves eroded the cliff, but left a flat platform behind. and cliffs can be found on headlands, since they are more open to the waves. Bays are more sheltered with constructive waveWaves which help build up material on the beach. They tend to have a low frequency and strong swash. which deposit sediment to form a beach. An example of wave-cut platforms can be found on the Glamorgan Heritage Coast at Porthkerry.
Cliffs and wave-cut platforms
Cliffs are shaped through erosion and weatheringThe breaking down of rocks in situ by the action of weather, plants, animals and chemical processes. . 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 rocky surface found at the foot of a cliff.
A wave-cut platform is formed when the following occurs:
- The sea attacks the base of the cliff between the high and low water mark.
- A wave-cut notchAn area of erosion at the base of a cliff formed by the waves. (small scale landform) is formed by erosional processes such as abrasionWhen rocks carried by the sea water wear away the landscape, eg cliff face/headland. and hydraulic actionErosion caused by the force of river water hitting cracks in the side of the river bank. The air in the cracks becomes compressed and then explodes outwards, breaking off bits of rock., this is a dent in the cliff usually at the level of high tide.
- As the notch increases in size, the cliff becomes unstable and collapses, leading to the retreat of the cliff face.
- The backwash carries away the eroded material, leaving a wave-cut platform.
- The process repeats. The cliff continues to retreat.
- Rock pools (a small scale landform) are left which often home a wide range of marine life as well as attracting many tourists.