UK Geographical issues:Coasts, rivers and geology Flashcards
What is hydraulic action?
When waves hitting the cliff forces pockets of trapped air into cracks expanding the cracks and breaking them apart.
What is abrasion?
When rocks picked up by the waves smash against the cliff wearing it away.
What is attrition?
When pebbles carried by waves become rounder and smaller as they collide with each other.
How are wave cut platforms created?
A wave cut notch creates an overhang which then collapses. the process repeats until there is a platform at the level of the wave cut notch.
Describe how longshore drift happens
When the swash is at an angle to the beach, it pushes the sediment up the beach at an angle and hence always moving the sediment down the beach
How are spits formed?
Long shore drift causes sediment to build up of at an angle when there is a change in the angle of the coastline. behind the spit, sheltered water becomes a salt marsh.
What are the five main changes in the
river as you go down from the upper to lower course?
1) river discharge (amount of water) increases
2) channel width increases
3) Gradient decreases
4) Cross profile flattens
5) sediment size decreases`
What is lateral erosion?
Erosion going sideways. e.g against the river bank
where do the rich fish keep their money?
river bank
Where do the poor fish keep their money?
Under the river bed
How to draw a cross section of a map from contour lines
1) use a piece of paper and mark on the first contour line from where u are starting and note down height
2) mark on all the other contour lines
3) stick it as the x axis on the graph have height going up the y axis
4) plot a cross at the height of each contour line and in the same point as the contour line on the x axis.
What does antecedent rainfall mean?
how much rain/moisture is already in the ground/drainage basin before further rain
What can happen to rain in the interception zone?
When the rain hits dense vegetation, a lot of the rain is held up by the plants and then evaporated into atmosphere or slowly dropped onto the ground.
What is infiltration?
when water is absorbed into the ground to make it saturated
What factors affect lag time?
- the density of vegetation causing the interception zone
- antecedent rain which causes the ground to be saturated and make surface run off
- transpiration
- Im/permeable ground
- gradient of valley/surrounding area
What is transpiration?
-water taken u by plants which is then evaporates into the atmosphere
What type of hydrograph is likely to show a river which easily floods?
A steep rising limb and a short lag time.
What are igneous rocks?
Rocks made from solidified magma, most are relatively resistant to erosion
e.g. granite
What are sedimentary rocks?
Rocks formed compressed sediment made from eroded material, sediment deposited my rivers and the erosion caused by the sea.
e.g. limestone
What are metamorphic rocks?
sedimentary rocks that have been further compressed and heated, hardening them.
e.g limestone becomes marble
slate
What rock type is typical of upland areas?
Igneous and metamorphic rocks because they are more resistant
What rock type is typical of low land areas?
sedimentary because they are less resistance.
How has passed events influenced the UKs landscape?
Glaciation: Glaciers pressed down, eroding the land into U shaped valleys
Tectonic activities: Magma came up though volcanoes, which when cooled formed igneous rock which is resistant meaning it didn’t erode as fast as the surrounding landscape.
What are the features of carboniferous limestone?
- Permeable
- Chemically weathered by rainwater
How do rock types influence the shape of the coastline?
- Soft rocks like clay are easily eroded by the sea meaning the coast will be dented in the form of bays as the softer rocks are eroded and the hard rocks are left as headlands
- Soft rock cliffs will be less rugged and less steep than hard rock cliffs
- Hard rock cliffs have wave cut platforms, caves, arches and stacks
What is the difference between a joint and a fault?
-joints are small cracks in the rock whereas faults are larger cracks in the rock, both making the rock more susceptible to erosion
What factors affect rate of erosion at the coast?
- geology
- Wave climate; how powerful, which direction, wave height and fetch (how far winds travel)
- currents and tides strength
- ground water levels (saturated cliffs are more vulnerable to erosion)
What are concordant coasts?
Coasts made from the same type of rock. These tend to have less bays and headlands
What are discordant coasts?
When the rock type alternates in layers perpendicular to the sea, forming bays and headlands.
What is swash?
When waves push sand and gravel up the beach
What is the name of the process by which sand and sediment is brought down away from the beach?
Backwash
What are constructive waves?
When waves deposit material onto the beaches because they have a strong swash and weak backwash
What are destructive waves?
Waves which erode material and sediment away from the beach because they have a weak swash and a strong backwash
What is traction?
When large boulders are rolled along the sea bed waves
What is the name of the process by which smaller stones are bounced along the sea bed?
Saltation
What is the name of process by which small particles are carried along in the flow of water?
Suspension
What is solution?
When some minerals are dissolved in sea water and carried with the water particles
What are the four wave transportation processes?
- Traction
- Saltation
- Suspension
- Solution
What are the impacts of development on coastal landscapes?
Negative
-the weight of buildings increases cliff vulnerability
-changes in drainage can cause cliffs to become saturated
Positive
-raises interest in protecting coastal landscapes
What are the impacts of Industry on coastal landscapes?
Negative
-can cause and increase in air, soil, water and noise pollution
-which can damage natural habitats
Positive
-Brings and incentive for coastal management to protect the coastline
What are the impacts of agriculture on coastal landscapes?
Negative -Increased soil erosion -increased sedimentation Positive -Wildlife habitats can be created/preserved from other types of development
What are the impacts of coastal management on coastal landscapes?
Negative -can increase erosion further along the coastline Positive - reduces risk of coastal flooding -prevents erosion -preserves salt marshes and spits
What are the impacts of tourism of coastal landscapes?
Negative
-increased development for hotels can destroy natural habitats and increase mass movement/cliff collapsing
-increase al types of pollution
Positive
-Increases value of land so that sea defences are built to preserve the land
