UK Physical Flashcards
How have active volcanoes helped to shape the UK landscape?
520m years ago, the UK used to be closer to plate boundaries. Active volcanoes forced magma through these boundaries and the magma cooled to form igneous rock e.g. granite
How have plate collisions helped to shape the UK landscape?
- Plate collisions caused rocks to be folded and uplifted forming mountain ranges.
- Many of these remain as the Scottish highlands or the lake district as the igneous rock is more resistant to erosion
- The intense heat caused by plate collisions formed hard metamorphic rocks in Scotland and Northern Ireland
How has plate movement helped to shape UK landscape?
- The UK used to be in the tropics 245-280m years ago meaning that carboniferous limestone would form. This can still be seen in upland areas like the peak district and south Wales and south West England
- Chalks and clays formed in Southern England most recently
What are the characteristics of granite?
- Very resistant
- Forms upland landscapes
- Has joints(cracks) that are unevenly spread which erode faster, forming tors
- Impermeable which forms moorlands
- An igneous rock
What are the characteristics of carboniferous limestone?
- Rainwater erodes the limestone through carbonation weathering creating limestone pavements, caverns and gorges
- Limestone is permeable forming dry valleys and resurgent rivers if limestone is on-top of permeable rock
- Sedimentary rock
What are the characteristics of slate and schist?
- Slate forms in layers creating weak planes in the rock. Very hard and resistant to weathering but is easily split into thin slabs
- Schist has bigger crystals than slate and splits easily into small flakes
- Both form rugged upland landscapes and both are impermeable creating waterlogged and acidic soils
- Metamorphic rocks
What are the characteristics of chalk and clay?
- Chalk is harder than clay and forms escarpments (hills) in lowlands and cliffs at the coast
- Chalk is permeable and water forms a spring when it meets impermeable rock
- Clay is soft and easily eroded. Forms wide flat valleys. Impermeable
- Both sedimentary rocks
How has glaciation helped to form UK landscapes?
- Glaciers eroded U-shaped valleys in upland areas like the lake district
- Glaciers deposited material as they melted e.g. large parts of Eastern England are covered in till deposited by the melting glaciers
How does mechanical weathering (salt weathering) erode coastlines?
- Seawater gets into cracks in the rocks
- When the water evaporates salt crystals form which expand and put pressure on the rocks
- This process repeated widens the cracks and causes the rock to break up
How does chemical weathering (carbonation weathering) erode coastlines?
- Carbon dioxide dissolved in seawater and rainwater makes them weak carbonic acids
- These weak acids react with rocks that contain calcium carbonate causing them to dissolve
How does biological weathering erode coasts?
-Plants grown into cracks in the surface of rocks, causing them to be pushed apart, breaking them down
What are the three processes of wave erosion and what are their characteristics?
Hydraulic action:
Waves crash into rocks and compress the air in the cracks. This puts pressure on the rock until eventually the cracks are widened enough for bits to break off
Abrasion:
Eroded particles in the water scrape and rub against the rock, removing small pieces
Attrition:
Eroded particles in the water smash into each other, breaking into smaller fragments and causing them to be rounded
What is mass movement and what are the three types?
The shifting of rocks and loose materials down a slope that happens when the force of gravity acting on a slope is greater than that of the force supporting it
The three main types are:
- Slides
- Slumping
- Rockfalls
What are the characteristics of destructive waves?
- High, steep and high frequency (10-14 waves per minute)
- Their backwash is more powerful than their swash
What are the characteristics of constructive waves?
- Low, long and low frequency (6-8 per minute)
- The swash is stronger than the backwash and so they deposit material
How are spits formed?
- They form at sharp bends in the coastline
- LSD transports sand and shingle past the the bend and deposits it in the sea
- Strong winds can cause the the end of the spit to curve, forming a recurved end
- The area behind this is protected from waves and so material accumulates there forming a mud flat or a salt marsh
How are bars formed?
- When a spit joins two headlands together
- The bar cuts off the the bay between the from the sea
- This can result in a lagoon forming behind the bar
How can landforms caused by erosion and deposition be seen on maps?
Caves: -Can't be seen Stacks: -Little blobs in the sea Cliffs: -Shown as little black lines Wave-cut platforms: -Shown as bumpy edges along the coast
Sand beaches: -Shown on maps as pale yellow Shingle beaches: -Shown as whit/yellow with speckles Spits: -Shown by a beach that carries on out to sea but is still connected to land at one other end
What impacts does agriculture have on the coast?
- Agricultural land is often left unprotected and so the coast is eroded naturally
- Vegetation can help stabilise clifftops by bringing the soil together. Removing it will leave the coast more vulnerable
- Sometimes marshland is reclaimed through draining, which increases the flood risk by removing the natural flood barrier
What impacts does development have on the coast?
- Areas of coast with lots of development have better costal protections due to their value
- However, costal protections here can make areas further along the coast more vulnerable to flooding
What impact does industry have on the coast?
- Costal quarries expose large areas of rock which are then more susceptible to chemical weathering
- Gravel has been removed from some beaches, increasing their risk of erosion
- Industrial growth has lead to salt marshes being built on which which increases the chance of flooding as salt marshes are natural flood barriers
What impact does costal management have on Coasts?
-Costal management can both prevent the coast from retreating where the protections are put in place, but also increase the risk of erosion further down stream
How do rising sea levels increase the risk of coastal flooding?
- Increase sea levels causes higher tides that flood costal areas more frequently
- Higher tides remove more sediment from beaches which increases their risk of erosion
- Rising sea levels expose more areas of the coast to erosion
How does storm frequency increase the risk of coastal flooding?
- Storms are becoming more frequent due to climate change
- Storms make the sea more powerful which means rocks will erode faster
- Since the sea is more powerful, it is able to move sediment around easier which means that some areas will be deprived of sediment more quickly and so will be more vulnerable
- Storm surges can become more frequent
What does the increase risk of flooding have on people?
- Low-lying costal areas could become permanently flooded and so impossible to inhabit
- Costal industries could be shut down because of flooding
- Infrastructure like roads and rail lines could be damaged
- Tourism may diminish, meaning that some may loose their livelihood
What impacts does the increased flood risk have on the environment?
- Ecosystems could be affected due to sea water increasing the salt levels, killing some organisms and reducing soil fertility
- The force of the floods can uproot trees and plants
- Some conservation areas could be eroded away
What is hard engineering and what are some examples?
Man-made structures built to reduce flooding and erosion. E.g.:
- Sea walls
- Groynes
What is soft engineering and what are some examples?
Using nature/natural defences to stop flooding and erosion e.g. :
Beach replenishment
Slope stabilisation
Strategic realignment
What is ICZM
Integrated Coastal Zone Management. It is an approach to protect the coast while taking everyone’s interests into account
What are the characteristics of rivers in the Upper, Middle and Lover Courses?
Upper:
-V-shaped, steep narrow sides, shallow channel, steep gradient
Middle:
-Gently sloping valley sides, wider, deeper channel, medium gradient
Lower:
Very wide, very wide deep channel, gentle gradient
What is vertical erosion and what is lateral erosion?
Vertical:
- Deepens the river valley, making it V shaped
- Dominant in the upper course
Lateral:
- Widens the river valley
- Dominant in the middle and lower course
How do the FOUR processes of erosion work in rivers?
Hydraulic action:
-The force of the water breaks rock particles away from the river channel
Abrasion:
-Eroded rocks in the river scrape and rub against the channel wearing it away. This is the most common form of river erosion
Attrition:
-Rocks in the river smash against each other. They become smaller and more rounded the further down the course they go
Solution:
-River water dissolves some types of rock e.g. chalk and limestone
What are the FOUR processes of river sediment transportation?
Traction:
-Large rocks are pushed along the river bed by the force of the water
Suspension:
-Small particles like silt and clay are carried along by the water
Saltation:
-Pebble sized particles are bounced along the river by the force of the water
Solution:
-Soluble materials dissolve in the water and are carried along
What are the FOUR reasons rivers deposit material?
- The volume of water in the river falls
- The amount of eroded material in the water increases
- The river is shallower e.g. the inside of a bend
- The river reaches its mouth
How is a waterfall formed?
- There is an area of hard rock on top of soft rock
- The softer rock erodes faster than the hard rock creating a ‘step’
- As the water flows over the step it erodes more and more
- A steep drop is created, called a waterfall
- The hard rock is eventually undercut and collapses
- The rocks are swirled around and through abrasion a plunge pool is created
- Over time this process continues, forming a gorge
How are meanders formed?
- The current is fastest on the outside of the bend
- More erosion takes place forming river cliffs
- The current is slower on the inside of the river, and material is deposited there forming slip-off slopes
How are levees formed?
- During a flood, the heaviest material is deposited closest to the river
- Over time this deposited material builds up and forms levees along the edges of the channel
From a map, how can you tell if a river is in the upper or lower course?
Upper:
- The surrounding land is high
- There are waterfalls
- It is a thin blue line and so narrow
- The river crosses lots of contour lines in a short space of time, showing that it is steep
Lower:
- The surrounding land is low
- The river doesn’t cross any contour lines
- There are meanders and ox-bow lakes
- The river is a thick blue line, showing that it is wide
How does climate affect the sediment load of a river?
- Rivers in wetter areas have a higher discharge
- Higher discharge increases the rate of erosion and so increase the amount of sediment in the river
- It creates V shaped valleys and a wide flat flood plane
- Transportation increases
How does geology affect a river’s sediment load?
- Rivers that flow through areas of hard rock have a lower sediment load as the rocks are harder to erode
- Rivers that flow through areas of soft rock have a greater sediment
- Landscapes with more resistant rocks have steeper valley sides
- Landscapes with less resistant rocks have gentle sloping valley sides
How do slope processes affect a river’s sediment load?
- Vertical erosion increases the movement of material down the slopes
- Mass movement increases the amount of material in a river
- Soli creep can add more finer particles to a river
How are hydrographs affected by physical and human factors?
Physical:
- Geology: Water runs of impermeable rock
- Soil type: Impermeable soils increase run-off, shallower soils become saturated faster that deeper soils
- Slope: Steeper slopes lead to increases run-off
- Drainage basin type: Circular basins have a higher discharge than narrower ones
- Antecedent (previous) conditions: Wet or cold weather increases run-off
Human:
- Urbanisation: Concrete and other impermeable surfaces increase run-off. Drains increase discharge
- Deforestation: trees take up lots of water, reducing fun off. Removing them increases run-off
Why is the flood risk increasing in the U.K?
Increased frequency of storms:
- The number of storms in the U.K are increasing due to climate change
- These storms are more extreme and so bring more intense rainfall
- More periods of wet wether mean that floods are more likely
Land use change:
- More urban areas are being built, increasing run-off
- Vegetation is being removed, increasing run-off
- Development is taking place on flood planes
What are the risks of flooding to people?
- People can be killed or injured
- Transport infrastructure can be damaged
- Floodwater can contaminate drinking water supplies
- People can become homeless and their houses damaged or destroyed
- People’s businesses may be destroyed or forced to close down
What are the risks of flooding to the environment?
- Contaminated floodwater can pollute rivers, damaging wildlife habitats
- Farmland can be ruined by the deposited silt and sediment
- River banks can be eroded, causing rivers to widen and increasing deposition
- Flooding can damage and kill plants
What are some hard engineering flood defences?
-Flood walls:
They allow the river to hold more water by artificially increasing the river bank’s height. However, are expensive and ugly
-Embankments:
High banks built near or along river banks. They stop rivers flowing into areas like towns, protecting them. Can be made of earth to blend into the landscape. Expensive to install.
-Flood barriers (flood gates):
Stop flooding from storm surges or very high tides. They can be shut when these are forecasted to protect the areas. Very expensive to install and must be constantly maintained
-Flood barriers (demountable):
They provide temporary protection from floods. They are put up when a flood is forecast. Expensive to install but don’t ruin the landscape
What are some soft engineering flood defences?
-Flood plane retention:
Stops any building on flood planes. This slows down flood waters. It is free but stops housing development and can’t be used in urban areas
-River restoration:
Makes rivers more natural by removing man-made structures like levees so the flood plane can flood naturally. This decreases the flood risk downstream as the river discharge is reduced. However it does increase the local flood risk
