The features of the UK coastlines are influenced by factors such as:
Some of the most recognisable coastal features include headlands, bays, cliffs and wave-cut platforms, as well as caves, arches, stacks and stumps.
Erosion from coastal winds, waves, rain and tides continuously shape and change these geological features.
Headlands are prominent, rocky outcrops extending into the sea, while bays are inlets where the land curves inward. These contrasting formations arise from the varying rate of erosion affecting different rock types.
Both headlands and bays are in a constant state of change. Coastal erosion and human activity can accelerate the process of formation, leading to dramatic changes across long geological time scales.
Headlands and bays are some of the most visually striking features you’ll see along the UK coastlines and bring tourists to coastal areas of the UK every year.
Headlands are areas of hard rock that extend out into the sea, formed due to their resistance to erosion. While the softer rock surrounding the headland erodes more quickly, the hard rock remains, giving the appearance of it protruding into the sea.
Bays are shaped by the erosion of soft rocks like clay and sand. As these materials are more susceptible to erosion, they wear away more quickly than hard rock, creating an indentation in the coastline. Bays provide a more sheltered area and are often lined with beaches.
Coastal erosion is mainly driven by powerful waves known as destructive waves. Destructive waves have high wave energy and have travelled long distances uninterrupted, building momentum.
These waves attack the coastline, leading to the formation of unique landforms.
Cliffs are prominent features shaped through erosion and weathering. Soft rock erodes more rapidly, forming gently sloping cliffs, while hard rock is more resistant and creates steeper cliffs.
A wave-cut platform is a wide, gently sloping surface found at the base of a cliff. It is formed through a series of steps:
1. The sea relentlessly attacks the base of the cliff between the high and low water marks.
2. This creates a wave-cut notch—a dent in the cliff, usually at the level of high tide—through erosional processes like abrasion and hydraulic action.
3. As the notch grows, the cliff becomes unstable and eventually collapses, causing the cliff face to retreat.
4. The eroded material is then carried away by the backwash, leaving behind a wave-cut platform.
5. This cycle repeats over time, resulting in the ongoing retreat of the cliff and the exposure of a wider wave-cut platform.
For example, below is the view of the wave-cut platform on the coast of Badouzi in Keelung, Taiwan.
Within headlands, erosion helps to form features such as caves, arches, stacks and stumps. These features are part of a natural process of erosion and typically form linearly.
1. The process starts with the widening of cracks within the headland because of erosional forces like hydraulic action and abrasion.
2. As the relentless waves continue to grind away at the cracks, they gradually enlarge and form caves within the headland.
3. Over time, these caves may grow larger and break through the headland, creating an arch—a natural bridge-like structure.
4. The arch’s base undergoes further erosion, widening it until its roof becomes too heavy and collapses into the sea, leaving behind a stack—a solitary column of rock.
5. The stack, exposed to the relentless waves, continues to erode at its base until it collapses further and forms a stump.