Coastal Landforms

Question 1

How are Headlands and Bays formed

Answer 1

Headlands and bays form where there are alternating bands of soft and hard rock
Discordant coastlne is one where bands of soft and hard rock run at right angles to the coast so the rocks erode at different rates. The protuding bands of isolated rock are called headlands
The formation of headlands and bays can take thousands of years

Question 2

How are Wave-Cut Platforms formed

Answer 2

1. Waves and rocks crash agasint the foot of a cliff face
2. The base of the cliff is eroded away, leaving a wave-cut notch
3. The unstable cliff collapses. With repeated erosion, the cliff retreats to form a wave-cut platform

Question 3

How are Caves, Arches and Stacks formed

Answer 3

1. Waves crash repeatedly into the headland, causing faults and joints to erode and develop into cracks and small caves
2. Constant erosion causes the caves to get bigger until their back walls are eroded away completely, creating natural arches
3. The arches widen as more rock is eroded away through weathering
4. The arches eventually collapse, leaving an isolated pillar known as a stack. Further erosion of the stack will leave a shorter stump

Question 4

How are Sand Dunes formed

Answer 4

1. Sand is deposited by longshore drift and blown to the top of the beach by onshore winds
2. Obstacles, such as driftwood, block sand movement, causing deposits to build over time
3. Vegetation (e.g. marram grass) helps to stabilise and bind the sand together, creating small embryo dunes
4. Over time, the dune migrates inland

Question 5

How are Spits and Bars formed

Answer 5

Spits are long stretches of sand or shingle that extend from the land. They form where the coastline suddenly changes shape (e.g. at river mouths or estuaries)
1. Sand and shingle are transported by longshore drift past the point where land ends
2. As the waves lose energy, material is deposited, forming a spit
3. Strong winds can cause the end of the spit to curve towards the land, creating a recurved end
In the sheltered area behind the spit, vegetation can grow easily, and a salt marsh may form.

Bars form when a spit joins two headlands together, trapping the water in a lagoon behind it