Coastal processes Flashcards
what is wave pounding?
the mass of water in a wave is very powerful. break against cliff and create shock waves
what is wave quarrying?
the action of waves breaking against unconsolidated material
what is hydraulic action?
weight of water forced into a joint traps air, causes pressure on rocks causing them to crack
what is abrasion/corrosion?
pebbles and stones are moved by waves and hurled against the cliffs.
what is attrition
the breaking down of already eroded rocks
solution/corrosion
the chemical reaction of seawater can corrode several rock types
what is frost shattering?
promoted by presence of large amounts of water
the salt water freezes
coastal rocks get severely cracked by the process
what is salt crystallisation?
evaporation of sea water leads to formation of salt crystals
as they grow they exert pressures within the rock causing it to gradually break apart
what is wetting and drying?
clays and shales are present they are prone to the expansion and contraction associated with wetting and drying
this results in cracks forming which weakens the rock and encourages rock falls
what is solution?
the effect of solution is to enlarge joints in the rocks creating pitted and jagged rock surfaces
what is biological action?
shellfish- adapted shell which means they can drill into rocks
seaweed- attaches itself to rocks and the force of the water can mean loose rocks can be prised from the floor
blue/green algae- secrete chemicals which promote processes such as solution
what are the types of mass movement?
soil creep mudflow runoff landslide/slump/slip rockfall
what is oxidation?
causes rocks to disintegrate when the oxygen dissolved in water reacts with some rock minerals
-evident as it stains rock surfaces yellow
what is hydration?
involves physical addition of water to minerals in the rock
causes rocks to expand
which causes cracks to be formed and chemical weathering to take place
`what is hydrolysis?
mildly acidic water reacts with minerals in rocks to create clays and dissolved salts.
this disintergrates the rocks
what is carbonation?
co2 dissolved in rainwater creates weak carbonic acid
reacts with limestone to create calcium bicarbonate
landslides
- triggered by earthquakes
- slip surface becomes lubricated and friction is reduced
- mass amount of material moves
rockfall
sudden collapse or breaking away of rock fragments
triggered by mechanical weathering
mudflows
involves earth and mud flowing downhill
slump
slide surface is curved rather than flat
commonly occur in weak unconsolidated land
soil creep
slow form of movement of individual particles downhill
particles rise towards the grounds surface due to wetting and freezing and then return vertically to the surface in response to gravity
runnoff
transfers both water and sediment from one form to another
small particles are moved downslope
solifluction
in summer the surface layer of soil thaws out groud becomes extremely saturated
slowly moves downhill by combination of heave and flow
traction
large stones/ boulders rolled/slide along beach
saltation
small pebbles and stones bounced along the sea bed
suspension
fine light material carried along by water flow
solution
dissolved materials transported within the mass of moving water
