Uks evolving physical landscape Flashcards
Granite
Upland areas
Very resistant
has joints that are unevenly spread
more joints ,the more weathering
impermeable
Slate and schsits
forms in layers creating weak planes in the rock
very hard and resistant to weathering easily split into slabs
impermeable leading to acidic soil
Carboniferous limestone
Rainwater eats away at the limestone through carbonation weathering
most of weathering happens at joins creating spectacular features
limestone is peremable
Chalk
Chalk is harder than clay and form hills at in lowland
cliffs at coast
chalk is permeable and forms springs where it meets impermeable rock
Clay
Soft and easily eroded
forms wide flat valleys in lowlands
impermebale
uk covered in ice
Uk went through many glacial periods
uk was coverered in massive sheets of ice
ice eroded landscapes carving u-shapped valleys
glaciers metled and deposited materials
What are the four physical processes that altered the landscape ?
Weathering
Erosion
post-glacial period
slope process
Weathering
the breakdown of rock
chemical ,mechanical,physical
Erosion
The wearing away of rocks
Post -glacial processes
3 ways
melting ice made rivers much bigger
rivers had more power to erode the landscape
melting ice created distinctive landscapes
slope processes
Mass movements-rockfalls ,slides ,slumps
What are physical processes affected by
Climate
Which are the three ways that humans have changed lanscapes ?
Agriculture
foresty
Settlement
Agriculture
arable
Dairy
sheep
humans have cleared landscape for farming
arable-flat land with good soil
Dairy -Warm and wet areas ,large grassy fields
sheep -harsher conditions in uplands
What do OS maps show ?
influence of agriculture ,show field lines,show drainage ditches
What is forestry
what can woodlands be used for ?
management of woodland areas
can be used for conservation,timber,recreation
was covered in deciduous landscape ,not a lot left
coniferous trees are being planted for timber
in some areas deciduous woodland is being replanted
Settlement
earky steelers
Early settlers -needed a water supply +somewhere that could be defended easily +sheltered from wind and rain
bridging points and availability of other resources
As settlements grew how did they further influence landscape ?
3 ways
the land was concreted affecting drainage patterns
rivers were diverted through underground channels
some rivers were straightened or had embankments built to prevent it from flooding
What is mechanical weathering ?
give main example
explain how it works
breakdown of rock without changing its chemical composition
Salt weathering
sea water gets into cracks
when water evaporates it forms crystals of salt
salt crystals form they expand putting pressure on the rock
repeated evaporation widens the cracks and causes the rock to break up
What is chemical weathering?
What is teh main example
The breakdown of rock whilst changing the chemical composition
Carbonating weathering -Seawater and rain have co2
dissolved in them making them weak carbonic acids .
carbonic acids react with calcium carbonate
What is biological weathering ?
breakdown of rock by living things
plant roots break down rocks by growing in the cracks and pushing them apart
What is mass movement?
Why does this happen (gravity)
What does mass movement cause
when are they more likely to happen
examples of mass movements ?
shifting of rocks and loose materials down a slope
the force of gravity is greater than the force supporting it
mass movements cause coasts to retreat rapidly
They’re more , likely to happen when material is full of water therefore the material is heavier
slides ,slumps and rockfalls
attrition
when pebbles in the river knock against each other ,they get smaller and more rounded
abrasion
When pebbles grind along the river bank and bed
solution
When water dissolves certain types of rocks
Hydraulic action
the sheer power of water as it smashes against river banks and compresses air in cracks putting pressure on the rock
repeated compression widens the crack and makes bits of rocks break off
Discordant coastlines
whats most likely to happen here?
What happens to the rate of eroded rock here
alternating bands of soft and hard rock at 90 degrees of the coast
erosional landscapes like heads or bays are more likely to happen here as bands of rocks are being eroded at different rates
concordant coastline
alternating bands of soft and hard rock that are parallel to the coast
here they are eroded at the same rate so less erosional landscapes
how does mild weather impact costal erosion
increases the rate of salt weathering and in mild temperatures the rate of coastal erosion will increase as the water evaportaes more quickly forming salt crystals more quickly
Explain what happens in winter (retreat )
What do winds create ?
rainfall ?
storms are very frequent in the winter
strong winds create high-energy destructive waves which increase erosion at cliffs .
intense rainfall can cause cliffs to become saturated makes mass movements more likely
destructive waves
explain the characteristics 3
whats increases erosional power ?
high, steep, and have high frequency
the backwash is more powerful than their swash, material is removed from the coast.
storms increase the erosional power of destructive waves
What kind of wind is the south coast exposed to ?
What kind of winds are common at east coast ?
warm south westerlies
cold northlys winds
Waves erode cliffs to form wave-cut Platforms
Waves cause most of the erosion to form at the foot of the cliff
this creates a wave-cut notch ,which is enlarged as erosion continued
after a while the rock on top of the wave cut notch will collapse as it becomes unstable
the collapsed material is washed away and a new wave cut notch starts to form
continues and rock continues to collapse resulting in the cliff retreating
how is material transported along the coast
explain the process
longshore drift
waves follow the direction of the prevailing winds
waves usually hit coast at oblique angles
swash carries material in that same direction
backwash carries material at a 90 degree angel
What are constructive waves?
When does deposition occur ?
characteristsics
What is more powerful ?
They are waves that deposit more material than what they erode.
long ,low ,slow frequency
when water carrying the sediment slows down so that it isn’t fast enough to carry sediment
swash is powerful as it carries material upcoast
backwash is weaker ,dosen’t take a lot of material down the coast
