coastal systems -landscape development (landforms of erosion) Flashcards
(19 cards)
what is a coastal landscape?
.made up of a number of landforms which give the each coastal landscape their key characteristics
what are landforms?
.individual components of a landscape
what are the landforms of erosion?
.cliffs and wave-cut platforms
.cliff profile features -caves, arches, stacks
where do cliffs and wave cut platforms found?
.at high energy coasts
what are the characteristic of a high energy coast?
.consistent strong destructive waves
.landforms of erosion
.rates of erosion exceed rates of deposition
.strong and steady prevailing winds
how are cliffs formed?
.destructive waves break at
the foot of a cliff which causes the foot of the cliff to become undercut -forming a wave cut notch
.a layer of rock is left above where the base used to be
.over time, as more destructive waves attack the base of the cliff, the wave-cut notch becomes bigger along with weathering causing the rock above to collapse so the cliff retreats
how are wave cut platforms formed?
.as the rock above the base collapses, the rubble is washed away by the waves, causing corrasion which forms a wave cut platform
why do wave cut platforms eventually stop?
.because waves will begin to break earlier so the waves energy will be dissipated before it reaches the cliff so the cliff cannot be eroded
what factors affect cliff erosion?
.lithology -how rock are arranged
what do horizontal beds and vertical beds of rock mean?
.horizontal beds -produce steep cliffs with notches were different erosion as taken place
.vertical beds -produce steep cliffs but there is less differential erosion
if a cliff has seaward dipping bedding planes what does this mean?
.means that loose material can slide down the bedding planes making a gentle cliff which is unstable and dangerous
what does it mean when a cliff has landward bedding planes?
.the cliff is relatively steep and stable
what is the sequence of how a headland erodes?
.crack
.cave
.arch
.stack
.stump
how are cracks formed?
.destructive waves attack weaknesses in the rock opening up cracks, this is where hydraulic action can occur which causes cracks to become wider
how are blowholes formed?
.when erosion in a cliff works in an upwards direction, it creates a passage from the base of the headland to the top, called a blowhole -when waves hit the headland, some water is forced up the blowhole and out the top
how are caves formed?
.as the cracks are eroded further, a cave is formed
how is an arch formed?
.if the cave is eroded right through the headland an arch is formed leaving a layer of rock above it which is vulnerable to weathering
how is a stack formed?
.when the layer of rock above the arch becomes weakened due to weathering, it eventually collapses leaving a stack of rock at the end of cliff
how is a stump formed?
.the weather and sea attack the stack until a stump is left which is often covered at high tide
