Coastal Landforms Flashcards
How “Wave cut platforms” are formed ?
1) Most erosion happens at the foot of a cliff
2) This forms a wave cut norstch which is enlarged over time
3) Repeated erosion causes the rock above the nostch to be unstable and collapse
4) Collapsed material is washed away=new nostch forms
5) Cliff retreats, leaving wave cut platform
How Headlands and Bays are formed?
1) Formed along a discordant coastline
2) Less resistant rock(like clay) is eroded faster (h.a. and abrasion)
3) This forms a bay
4) More resistant rock (like chalk) eroded slower, creating a headland
How caves are formed?
1) Starts from a crack
2) Waves crash into crack (h.a. and abrasion) enlarge the crack
3) Over time cave is formed
How arches are formed?
Continued erosion deepens the cave, until eventually it becomes an arch
How stacks are formed?
Weathering and erosion continues to wear away the rock supporting the arch, until it collapses
How stump is formed?
Further erosion of the stack will leave a shorter stump
How sandy beaches are created ?
- Occur where there are constructive waves
* small sand particles=easily carried by backwash=beaches are long and shallow
How shingle beaches are formed?
- Occur where there are high energy waves
- Large sediment is left on the beach
- weak swash=short and steep
How spits are formed?
Longshore drift transports sand and deposit in the sea
Strong wind and waves curve the end
The area behind the spit is sheltered so plant can grow there
How bars are formed?
Bar form when a spit joins two headlands together
The bay between headlands gets cut off from the sea
Lagoon forms behind the bar
What is an offshore bar?
Is when it’s not connected to the coast aa friction with the bed causes waves to slow down and deposit sediment offshore
