coasts Flashcards
what is the difference betweeen a constructive and a detsrucvtive wave
constructive wave strong swash weak backwash low waveheigth destructive strong backwash weak swash steep wavefront
how is a wave cut platform formed
when waves break against a cliff the wave takes a bite out of the cliff
a wave cut notch
as the notch gets deeper the overhanging rock can no longer support itself and it collapses onto itself
in its place the retreating cliff leave a gently sloping platform called a wave cut notch.
how is a headland formed
when hard rock is next to soft rock differential erosion causes rock to erode at different speeds.
THe harder rock forms a headland
because bays are sheltered depostion occursas there are less powerful waves
how is a salt marsh formed
material is transported along the coastline by LSD
when there is a bend in the coastline material is deposited, this is due to counter currents and a loss in velocity
the material then builds up to form a ridge extending out to the sea. Spit curves due to change in prevailing wind direction
behind spit [arts of mud are built up behind to form a slat marsh
how are beached formed
they are formed by the deposition of material along a coastline by longshore drift sandy beached are formed where there are sheltered bays which are much wider than usual bays.
pebble beached are found where cliffs are being eroded
large rocks are found towards the backs of beaches at lines of high energy.
formation of a bar
when material is transported along the coastline by LSD =, when there is a headland formed then this means this grows along the coastline eventuall forming a bar leaving a lagoon behind. deposition occurs due to a loss in energy, deposition of constructive waves/s;
how is a stump formed
because of processes like hydraulic action there is a hole in a cave.
due to further erosion this leaves an arch as it has eroded all the way through
over time the arch can’t hold itself and therefore collapses under its own gravity, this causes a stack
further erosion causes there to be a stump
coastal management techniques and advantages
sea wall often includes a walk way rock armour disssipates the waves energy gabions ease of handling speed of construction quick to construct. groynes expensive but quick to construct
soft management techniques
beach nourishment when sand is punched onto a beach
sediment is redistributed from the lower to upper part of the beach
dune nourishment planted marram grass, stabilises dunes
off shore reef material can be placed in the intertidal some parralel
soft management techniques
beach nourishment when sand is punched onto a beach
sediment is redistributed from the lower to upper part of the beach
dune nourishment planted marram grass, stabilises dunes
off shore reef material can be placed in the intertidal some parralel
headland is formed along a discordant coastline
