Erosion- the process and landforms Flashcards Preview

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Flashcards in Erosion- the process and landforms Deck (23)
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factors that influence erosion

human intervention
wave type
discordant vs concordant coastlines


types of transportation

traction (large particles pushed along)
suspension (small particles carried in the water)
saltation (small particles bouncing along sea bed)
solution (dissolved in water)


two factors that influence transportation

energy and size


groynes create a ___ feedback



why do groynes create a __ feedback?

positive because they increase erosion downwind as groynes starve the beach downwind of sediment


sea walls create a _____ feedback ... because...

positive, as they deflect the waves backward keeping the energy and transferring elsewhere -- increasing erosion downwind


what is a high energy coastline

small particles easily transported whilst larger and heavier material is deposited, forming shingle beaches


what is a low energy coastline

even the smallest matter is deposited forming mudflats and salt marshes


what is wave quarrying (type of erosion)

a breaking wave traps air as it hits the cliff face
the air is compressed into any gaps causing large pressure
as wave retreats there is an explosive effect of the air pressure being released
weakens cliff face- removes large chunks


concordant coastline definition

rocks on these coastlines run parallel to the sea


discordant coastline definition

rocks on these coastlines run perpendicular to the sea


formation of a stump IN DEPTH EXPLAIN

headland is attacked by wave quarrying, HA and solution. erosion begins where waves find a line of weakness in the rock and erode laterally and backwards , forming a cave
if the weakness runs through the headland two caves may form back to back, forming an arch
waves continue to erode the base and sub-aerial processes attack the roof of the arch- roof collapses- leaves a headland and a stack
attacked by biological, physical and chemical weathering and erosion until it collapses leaving a stump which is covered at high tide


how does a wave cut platform reduce erosion in the future

although they rarely extend more than a few hundred metres WCPs slow down the waves as they have further to travel in shallow water. so they tend to break earlier and dissipate their energy before they can erode the cliff reducing the rate of erosion.
-- note that WCPs are made out of hard rock


a cliff profile refers to ...

how steep the cliff face is at its meeting point with the sea


if the bedding planes (the layers of rock that make up the cliff) are HORIZONTAL then...

the cliff profile will be stable with a steep cliff face


how can tectonic movement affect bedding planes

rock can be uplifted and folded. can change the alignment of the strata in the cliff face


rock that has been lifted with its bedding planes tilted downwards away from the coast create...

very stable cliff profiles. rates of erosion will be slow as the cliff is supported by deeper running strata


bedding planes that tilt upwards have ... because...

cliff profile similar to the angle of tilt due to frequent mass movements that occur when the base of the cliff is eroded


bedding planes are tilted towards the sea create a ...

unstable beach profile as there is a gravitational pull on the rock, vulnerable to erosion


actual examples of stacks and caves

halsenifs hellir beach in Iceland-- southern Iceland, east of Reykjavik


actual example of a stump

stump beach in east California


example of a cliff

etretat cliffs in france


example of an arch

Dyrholaey in south Iceland, southeast of Reykjavik