U.k 4.3 Flashcards
What is a concordant coastline?
- Same rock
- resistant rock like limestone
- cliffs
What is a discordant coastline?
- different rock types
- weaker rock like sandstone
- more common
- arch, stacks and stumps
How does rock type affect landforms?
The weaker the rock type (sedimentary) the quicker the land will erode.
What are joints and faults?
- both are cracks in sedimentary rock to layering of rock
- joints can be eroded away by acid rain to form stumps
- faults cause earthquakes through tectonic plates
What are features of constructive waves?
- long wave length
- low wave height
- common in summer
- low wave frequency 6-8 per minute
- stronger swash than backwash
- surging waves forward
What are features on destructive waves?
- short wave length
- high wave height
- common in winter
- high wave frequency 10-14 per minute
- stronger backwash than swash
What is longshore drift?
Waves flow forward at the same direction as the wind. Strong backwash pulls sediment along the beach. Groynes used to stop sediment flowing.
How can destructive waves affect lands?
Waves crash against cliffs slowly eroding the bottom of the cliff. Once enough of the cliff has been eroded away, the top collapses under the weight removing large chunks of land. Rock armour is rocks placed along shores to stop waves eroding the cliffs.
How do spits form?
Longshore drift moves sediment along a beach until it reaches a headland. The sediment slowly pushes out across the river. It can’t connect as it doesn’t have another headland so it traps sediment in the spit instead.
What are bars?
Bars are made by the same process as spits when longshore drift moves sediment but two headlands are involved so connect. The water trapped behind the bar is called a lagoon.
Explain the process forming caves, arches, stacks and stumps.
- large crack opened by hydraulic action
- crack erodes away into a cave
- cave becomes larger
- cave breaks through headland
- arch erodes and collapses
- leaves a stack
- stack erodes down into a stump
