Erosional landforms
The process of erosionThe wearing away of pieces of rock, soil or other solid materials. can create different landforms along the coastline.
Headlands and bays
Cliffs along the coastline do not erode at the same pace. When a stretch of coastline is formed from different types of rock, headlandA high area of land that extends out into the sea. and bayA low-lying inlet of land on the coast. can form.
Bands of soft rock such as clay and sand are weaker and therefore they can be eroded quickly. This process forms bays. 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 headland.
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.
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. is formed by erosional processes such as abrasion and hydraulic action - 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.
Caves, arches, stacks and stumps
Caves, arches, stacks and stumps are erosional features that are commonly found on a headland.
- Cracks are formed 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.