2. Coastal Erosion Features- Headland, Bay, Cave, Arch, Stack and Stump
Red writing- opportunity to expand answer by explaining one/all forces of erosion
Headlands and Bays
There are bands of hard and soft alternating
rock, which lie at right angles to the sea.
Destructive waves attack the bands of hard
and soft rock, causing them to erode.
Destructive waves are formed where the
backwash is greater than the swash, making
them forceful and powerful and able to carry
materials away from the coast.
The destructive waves work with the forces of
erosion (Hydraulic Action, Solution, Corrasion
and Attrition) to erode the coastline.
The hard rock (granite) is eroded much more
quickly than the soft rock because the
composition of the rock makes it harder to
erode. It is left protruding out into the sea,
causing a headland to form. Eg. Handfast Point.
The soft rock (sandstone) is eroded much more
slowly than the hard rock. The soft rock is cut back by the waves to form a bay, often
with a sandy beach. Eg. Durlston Bay.
CfE Higher Geography
Dalziel High School
D.Gallacher 2015
Caves and Arches, Stacks and Stumps
The headland is left protruding out into the sea and is continuously attacked by the
destructive waves. Destructive waves are formed where the backwash is greater than
the swash, making them forceful and powerful and able to carry materials away from
the coast. The destructive waves work with the forces of erosion to erode the
protruding headland.
1.Hydraulic Action attacks weaknesses in the headland like joints or faults. The force
of the water pressurizing the weaknesses makes them wider and deeper causing a crack
to form.
2.Solution attacks the crack, the salts or acids in the water chemically react with the
rock and dissolve it. This makes the crack become wider and wider over time, eventually
giving way to form a cave. Eg. Tillywhim caves.
3. Often, two cave are formed back to back. The process of corrasion (the sea
propelling rocks using the wave power against the headland causing vibrations and
fractures in the rock) deepens the two caves, until they meet in the middle, causing and
arch to form. Eg. Durdle Door.
4.The arch is attacked by the force of the waves and becomes wider and wider. As this
happens, the roof becomes unsupported, cracks grow and the rock fractures. The roof
then collapses and falls into the sea. The pillar of rock is left standing alone in the sea
called a stack. Eg. Old Harry
5. The stack is continuously attacked by the force of the waves. The waves attack the
base and a wave cut notch is formed in the stack. This causes it to get weaker and
weaker. The rock above the wave cut notch cannot be supported and falls into the sea,
creating a stump. Eg. Old Harry’s wife
CfE Higher Geography
Dalziel High School
D.Gallacher 2015