Coastal changes and conflict Flashcards
Describe concordant coasts
- made up the same type of rock
- parallel to the sea
Describe discordant coasts
- rocks type alternates in layers
- perpendicular to the sea
- forms headlands and bays
What are joints ?
small cracks in rock
What are faults ?
larger cracks in rock
Rates of erosion are mainly down to the geology, but what are the other 4 factors ?
(1) geology structure - e.g if soft and hard rocks occur together
(2) ‘wave climate’ - how powerful waves are, wave direction, wave height and how far they travel over open water
(3) local currents and tidal range
(4) groundwater levels - high groundwater is more vulnerable
Describe the formation of headlands
- headlands are left sticking out where hard rock has resisted erosion (erosion of the sock rock forms bays)
- they become more vulnerable to erosion because wave energy is concentrated there
Describe the formation of bays
- bays form due to rapid erosion of soft rock / less resistant rock
- they then become sheltered by headlands and stop eroding
How are caves formed ?
when the waves erode a weakness in the rock e.g a joint or a fault
How are arches formed ?
when two caves erode back from either side of a headland and meet in the middle
How are stacks formed ?
when an arch collapses
How are stumps formed ?
when a stack is eroded by wind and water
What are wave cut platforms and how are they formed ?
- areas of flat rock at the base of the cliff
1. rock face overhangs
2. wave-cut notch is undercut by the waves
3. cliff retreats inland and overhanging rock collapses
4. wave-cut platform is formed
What are the 4 process that erode the coast ?
- hydraulic action
- abrasion
- attrition
- solution
Describe how hydraulic action erodes the coast
- the sheer weight and impact of water against the coastline, will erode the coast
- waves compress air in cracks in rock, forcing them apart and weakening the rock
Describe how abrasion erodes the coast
breaking waves throw sand and pebbles against the coast during storms