coasts Flashcards
how is igneous rock formed
characteristic?
when molten rock cools down and harderns
crystals
2 examples of igneous rock
basalt and granite
how is sedimentary rock formed
when layers of sediment are compacted together until it becomes solid rock
3 characteristics of sedimentry rock
softer,easily eroded and layers
2 examples of sedimentary rock
sandstone and chalk
how is metamorphic rock formed
when other rocks are changed by heat or pressure
2 characteristics of metamorphic rock
harder and more compact
an example of metamorphic rock
clay ➡️ slate
what rocks do upland areas of uk consist of
more resistant igneous and metamorphicrocks that have eroded slowly over time
what rocks do lowland areas consist of
younger sedimentary rocks that form rolling hills and valleys and are alot less resistant to erosion
case study: Dartmoor
where?formed?human activity effecting?
upland south east england granute cooled and solidified from molten rock made of granite ( igneous) moorland and hilltops deforestation and mining
case study: South downs
where?formed?effected?
lowland
southern devon
marine deposits that made chalk fountains during createous period
downs/hills/valleys
erosion caused slopes and hills from ice age weathering caused v-shaped valleys
what are the 5 physical processes
weathering deposition transportation mass movement erosion
3 types of weathering
mechanical
biological
chemical
deposition
when sea loses energy, it drops the material it has been carying
4 factors that lead to deposition
constructive waves
shallow water
sheltered areas
little or no wind
transportation
the movement of sediment alaong a coastline
4 types of transportation
solution
suspension
saltation
traction
mass movement
the downhill movement of sediment that moves due to gravity
4 types of mass movement
rockfall
muddlow
landslide
rotational
erosion
wearing away of roack along a coastline
are constructive or destructive waves responsible for ersosion?
destructive
4 types of erosion
hydraulic action
abrasion
attrition
solution
mechanical weathering
sea water gets into cracks and evaparates and salt crystals expand
chemical weathering
rain falls on rocks and a weak chemical reaction occurs
biological weathering
plant roots break down rocks and then grow in cracks
hydraulic action
waves crash against the rocks and compress air in cracks with causes rock to widen
abrasion
particles rub against the rock
attrition
particles smash into eachother and break into smaller fragments
solution
disolved CO2 makes sea acidic and the acid reacts chemically with the rock
rockfall
bits fall off the face of the cliff
mudflow
saturated soil flows down
landslide
large blocks of rock slide downhill
rotational slip
saturated soil slumps down a curved surface
solution
minerals in rocks are dissolved in sea water then carried in solution
suspension
small particles are suspended in the flow of the water
saltation
small pieces of shingle or large sand garins are bounced along the sea bed
traction
pebbles are rolled along the sea bed
longshore drift definition
movement of materail along the coastline
process of longshore drift
waves aproach the coast at the angle of the prevailing wind and the waves break down the sediment in the rock
swash carries materail towards beach
backwash flows back to the sea
process rrpeats in a zigzag motion
constructive waves
characteristics? found? season?beach?
builds up beaches and stronger swash
sheltered bays and spits
more common in summer
builds up sandy beaches
destructive waves
characteristics?found in?season?beach?
erodes headlands and stronger backwash
exposed bays
more commen in winter
builds up pepple beaches
fetch
2 factors that create long fetch
length of water the wind blows over
strong wind and long amount of time
4 steps of how waves are formed
1) wind blows acriss ocean
2) wind pushes parts of water down
3) inturn pushed other parts of water up
4) these areas start spinning in a cycle begining to form a wave
crest
top of a wave
wave length
distance between 2 crests
wave frequency
number of waves breaking per minute
swash
waves carrying sediment towards land
backwash
the waves draging sediment back into the ocean
how headlands and bays are formed
when there alternating bands of resistant and less resistant rock along a coast
how wave cut platforms and cliffs are formed
destructive waves attach bottom of the rock and the waves under crack the cliff
it gets deeper and the overhanging cliff above becomes unsupported and eventually colapses
how coves form
the harder rock acts as a barrier but if breached the sea is able to erode the softer rock behind
caves,arches,stacks and stumps are ……
features that are commonly found on……
erosional
headlands
formation of caves
as waves continue to grind away at the crack it begins to open and form a cave
formation of arches
caves become larger and eventually break through the headland
formation of stacks
base of arch continually becomes wider through erosion until its roof becomes too heavy and collapses into the sea
formation of a stump
when a stack is undercut at the base until it collapses to form a stump
formation of bars
laggoons?
spits grow across a bay and join 2 headlands together
they can sometimes trap shallow lakes behind the bar these are known as lagoons
formation of spits
occur when there is a change in shape of the landscape
sediment is carries by longshore drift,depostition occurs and a long ridge of material is deposited
depositional landforms
the build up of deposited sediment can form different features along the coast
3 depositional landforms
beaches
spits
bars
4 examples of erosional landforms
headlands and bays
wave cut platforms
coves
caves,arches,stacks,stumps
soft engeneering
sustainable and natural approach to managing the coast
3 soft engineering strategies
beach nourishment
reprofiling
dune nourishment
beach nourishment
posatives?
negatives?
sand is pumped onto beach&it builds up
blends in and good fir tourism
needs constant replacement
reprofiling
posatives?
negatives?
sediment redistributed from lower to upper part of the beach
cheap,simple,reduces wave energy
must be low wave energy ,needs constant repeating
dune nourishment
postatives?
negatives?
grass planted on sand dunes which stabalises and traps sand & builds up
cheap and natural looking
damaged by storms
why do coasts need to be protected?
to protect homes and businesses
prevent damage and destruction
protect wildlife
for research
hard engineering
building artificial structures to control natural processes
4 types of hard engineering strategies
sea wall
rock armour
gabions
groynes
coastal recession-
effects?
land and properties lost at sea due to flooding
farms at risk/jobs lost/financial loss
3 human activities that effect coastal erosion and recession
industry
urbanisation
agriculture
effect of storm surges
homes&businesses vunrable to flooding coastal industries shut down damage to infrastructure pit tourists off visiting houses,businesses,farms lost at sea
sea wall
posatives?
negatives?
concreate walls placed ata foot of a cliff prevents erosion & reflects wave energy
effective/can walk on the beach
expensive/can be brocken down
rock armour
posatives?
negatives?
large boulders at foot of cliffs that breaks waves and absorbs wave energy
cheap/easy to maintain
expensive/don’t fit in with the landscape
gabions
posatives?
negatives?
rocks in mesh cages to prevent erosion
cheap
not stronh/look very unnatural
groynes
posatives?
negatives?
wooden/rock structures placed along beach at a right angle to the sea
encourages tourism
increases erosion somewhere else
prevents longshore drift-traps sediment
