coasts Flashcards
what are constructive waves?
calm, not very tall, deposit material to build the beach, low frequency, deposition, swash stronger than backwash
what are destructive waves?
backwash stronger than swash, break down beach, high frequency, tall, erosion
what are the two types of weathering?
chemical and mechanical
what happens in chemical weathering?
the chemical composition of material changes
what is an example of chemical weathering?
acid rain, caused by carbon dioxide dissolving in the atmosphere, the acid rain hits rock and dissolves it
what is the main type of mechanical weathering?
freeze-thaw
what happens in freeze-thaw weathering?
in cold climates, water enters cracks and freezes, as it freezes the crack expands, meaning it fills with more water and the process repeats
what is weathering?
the natural processes that break down rock
what is mass movement?
the large movement of soil or rock down a slope or cliff-face
what are the main causes of mass movement?
weather, erosion, gravity
what are the three examples of mass movement?
rockfalls, sliding, slumping
what happens with rockfalls?
when materials crumble and break down the cliff
what happens with sliding?
materials move down a slope in a straight line
what happens with slumping?
when material moves down a slope at a curve
what are the four erosional processes?
hydraulic action, abrasion, attrition, solution
describe what happens with hydraulic action
water fills cracks and causes them to expand
describe what happens with attrition
where different rocks hit against each other and cause each other to get smaller and round
describe what happens with abrasion
rocks bounce along the sea bed and become smaller as they break apart
describe what happens with solution
rocks like chalk dissolve in slightly acidic water
how are wave-cut platforms formed?
destructive waves erode the bottom of cliff, forming a wave-cut notch; the rock above it collapses as it has no support; destructive waves continue to erode, forming another wave-cut notch; more debris falls without any support and the cliff beings to retreat backward
where are headlands and bays formed?
alternating bands of hard and soft rock
what forms at a band of hard rock?
headlands
what forms at bands of soft rock?
bays
what landforms form at bands of hard rock?
caves, arches and stumps
how are caves formed?
cracks at headlands are eroded by hydraulic action
how are arches formed?
caves erode fully from one side to the other
how are stacks formed?
when the top of an arch falls due to gravity
what are the four transportational processes?
suspension, saltation, solution, traction
what is solution (transportation)?
rocks like chalk dissolve in slightly acidic water and are carried
what happens in suspension?
when insoluble rocks are carried by the water but not dissolved
when happens in saltation?
small rocks bounce along the bed of the sea, traveling in the direction of water
what happens in traction?
where large rocks are dragged along the sea bed by the current
what is hard engineering?
protecting coastlines from erosions using man-made structures
what is soft engineering?
manipulating natural structure so protect coastlines from erosion
where is the holderness coastline located?
north-east of England
how far does the holderness coastline retreat every year?
1-2 metres
