coasts Flashcards
whats a constructive wave?
-stronger swash
-long wavelength
whats a destructuve wave?
-stronger backwash
-short wavelength
size of wave depends on…
-fetch
-wind speed
-amount the wind blows
long shore drift…
-waves approach the beach at an angle
-as waves break, swash carries material up the beach at the same angle
-as swash dies away the backwash carries material down the beach at right angles
-the process repeats
-transporting material in a zig zap movement
what is a wave-cut notch?
where the wave has undercut the rock
process of cliff retreat and wave cut platform…
-abrasion, corrasion and hydraulic action further extend the notch back into the cliff
-undercut continues, cliff becomes unsupported and collapses
-backwash carries away eroded material leaving behind a wave-cut platform
-process repeats and cliff continues to retreat
how is a headland and bay formed?
-less resistant rock is eroded back (forming bay)
-more resistant rock sticks out as a headland
caves, arches and stacks…
-wave approaches shore, (speed reduces) changing wave angle
-wave refraction occurs causing erosion on all sides of headland
-cracks widen as abrasion begins to wear away forming cave
-cave becomes larger, eventually breaks through headland forming an arch.
-arch base widens and eventually roof collapses leaving behind stack
-stack is undercut at base by wave action until it collapses to form a stump.
characteristics of a spit and what is it?
-long and thin
-curved
-made of sand shingle
-extended stretch of sand extending out to sea from shore
-occur when change in coastline
formation of a spit…
-wave aproches beach at an angle
-as wave breaks the swash carries material up
-when wave dies down, backwash carries material down
-(sediment transported by longshore drift)
-sheltered area allows for deposition of sediment
-due to inc friction more deposition occurs
-spit slowly build up where there is headland
sand dune formation…
-wind-blown sand is deposited against an obstruction pebble as more particles are caught
-veg grows on it
coral reef requrements?
-warm water
-salty water
-light for photosynthesis
-clear water
-water circulation
mangrove requirements?
-shallow water
-high level of rainfall
-gentle waves
-warm temp
-salty water
mangrove characteristics…
-snorkel like roots
-filtration system keeps sald out
-ideal temp of 27
-need high humidity levels
-trees that live on coastline
coast opportunities…
-swimming/leisure
-industry
-fishing
-ports and harbour
-tourism
-agriculture
