Topic 4-UK Geographical Issues Flashcards
Upland Areas
Tend to be North and West of the UK
Lowland Areas
Tend to be South and East of the UK
Igneous Rocks
Formed when magma from the mantle cools down and hardens. The rock forms crystals as it cools. Igneous Rocks are usuall hard
Examples of Igneous Rocks
Basalt
Granite
Obsidian
Sedimentary Rocks
Formed when layers of sediment are compacted together until they become solid rock.
Examples of Sedimentary Rocks
.Limestone-formed from tiny shells and skeletons of dead sea creatures. Limestone is hard and resistant
.Clays and Shales-made from mud and clay minerals. Very soft and weak resistance
Metamorphic Rocks
Formed when other rocks are changed by heat and pressure. The new rocks become harder and more compact.
Examples of metamorphic rocks
Slate
Schist
Ways tectonic processes have shaped the UK
Active Volcanoes
Plate Collisions
Plate Movements
Active Volcanoes
Forced magma through Earth’s crust which cooled and formed igneous rocks
Plate Collisions
Caused rocks to be folded and uplifted forming mountain ranges
Plate Movments
345-280 million years ago Britain was in the tropics and higher sea levels meaning it was partially submerged under water
Granite
.Very resistant,forms in the uplands and has cracks which aren’t evenly spread.
.Impermeable meaning it doesn’t let water through. Creating moorlands.
Slate
Forms in layers creating weak planes of rock. Generally very hard and resistant to weathering and is impermeable
Schist
Has bigger crystals than slate and splits easily into small flakes and are impermeable
Carboniferous Limestone
.Rainwater eats away at limestone through chemical weathering.
.Most weathering happens at joints (cracks)
.Permeable meaning they allow water to pass through
Chalk
.Harder than clay
.Forms escarpments and cliffs in the lowlands
.Permeable
Clay
.Very soft and easily eroded
.Forms wide flat valleys in UK lowlands
.Impermeable so water can’t pass through
Glacial Processes involved in shaping the UK
There have been many glacial periods in the UK. Ice is powerful so it was able to erode the landscape carving out large U-shaped valleys in the uplands such as the Lake district. Glaciers also deposited lots of material as they melted resulting in England being covered in till which is an unsorted mixture of clay sand and rocks.
Physical processes involved in shaping the UK
Weathering
Erosion
Post Glacial Processes
Slope Processes
Weathering
Weathering is the breakdown of rock into smaller pieces
It can be mechanical,chemical or biological
Erosion
Wears away rock. During the glacial periods ice eroded the landscape. Rivers and Sea constantly erode the landscape
Post-Glacial river processes
Melting ice at the end of glacial periods made rivers much bigger than normal with more power to erode the landscape. The ice also left distinctive landforms when melted.
Slope Processes
Mass movements such as rockfalls,slides,slumps and soil creep
How physical processes formed the Uplands
.Llyn Idwal is a tarn. It sits in a corrie that was hollowed out during glacial times
.Freeze-Thaw weathering occurs on the steep back wall of the corrie. As the rocks are broken up there are rock fall which forms scree slopes
Dry Valleys
Found in UK lowlands. These valleys have no visible river but rather flow underground in permeable chalk. These were formed duting the glacial periods.
How humans have shaped the landscape
Agriculture
Forestry
Settlement
Agriculture
Different landscapes are best for different types of farming
Arable
Dairy
Sheep
Arable Land
Flat land with good soil used for growing crops
Dairy Land
Warm and wet areas. Are good for dairy farming and there are lots of large grassy fields
Sheep
Sheep farming takes place in harsher conditions in the uplands. Sheep farming takes lack of trees in hills. Sheep farming is also called pastoral
Forestry
Is the managment of areas of woodland. Coniferous forests have been planted for timber. These trees are often planted in a straight line. When areas are felled the landscape is left bare. In some places deciduous woodland is being replanted to return area to a more natural state
Settlement
As settlements grew they further influenced the landscape
.land was concreted for roads and buildings which affected drainage patterns
.some rivers were diverted into underground channels
.some river channels were straightened or had embankments to prevent flooding
Mechanical Weathering
Breakdown of rock without changing it’s chemical composition
Mechanical Weathering that affects coasts
Salt Weathering-Sea water enters cracks, the water evaporates and crystals form which pits pressure on the rock causing it to widen and crack
Chemical Weathering
Is the breakdown of a rock by changing the its chemical composition
A type of chemical weathering
Carbonation weathering-rainwater being slightly acidic due to CO2 reacts with rock containing calcium carbonate causing rocks to dissolve from rainwater
Biological weathering
Is the breakdown if rock by living things eg plant roots break down rocks by growing into cracks and applying pressure
Mass Movement
Is the shifting of rocks and loose material down a slope
3 types of mass movement
Slides-material shifts in a straight line
Slumps-material shifts with a rotation
Rockfalls-material breaks up and falls down slope
3 types of erosion
Hydraulic Action
Abrasion
Attrition
Hydraulic Action
Waves crashing against rock and compresses the air into cracks. This puts pressure on the rock.
Abrasion
Eroded particles in the water scrape and rub against rock,removing small pieces
Attrition
Eroded particles in the water smash into eachother and break into smaller fragments
Discordant Coastlines
Coastlines that are made up of alternating bands of hard and soft rock that are right angles to the coast
Concordant Coastlines
The alternating bands of hard and soft rock that are parallel to the coast.
Bays And Headlands on Discordant Coastlines
Are most common on discordant coastlines because bands of rocks are being eroded at different rates
How the UK climate impacts on coastal erosion and retreat
Temperature are coldest in winter and have highest frequency of storms. The strong winds create high energy,destructive waves increasing erosion of cliffs.
Destructive Waves
Stormy conditions out at sea
Frequent waves 10-14 waves per min
Backwash more powerful tha swash meaning material is taken away from shore
Constructive Waves
Calmer conditions out at sea
Low wave frequency 6-8 waves per min
Swash stronger than backwash meaning material is deposited onto the shore.
How wave cut platforms form
.Waves cause most erosion at the foot of the cliff
.The rock forms a wave cut notch,which is enlarged as erosion continues
.The rock above the notch becomes unstable and eventually collapses
.The collapsed material is washed away and new wave-cut notch starts to form
.Repeating collapsing results in the cliff retreating
.A wave cut platform is formed
Soft Rock or rocks with lots of joints
Low resistance to erosion
Hard Rocks
High resistance to erosion
Bays
The less resistant rock are eroded quickly forming a bay
Headland
The resistant rock is eroded more slowly therefore leaving the rock jutting out forming a headland
How Caves,Arches and Stacks are formed
.Waves crash into headlands and enlarge the cracks by hydraulic action and abrasion
.Repeated erosion and enlargement of cracks forms a cave
.Continued erosion deepens cave eventually breaking through the headland forming an arch
.Erosion continues to wear away the rock supporting the arch until it eventually breaks of forming a stack
Longshore Drift
The transportation of material along a coast
How longshore drift deposits material
.Waves follow the direction of prevailing wind
.This usually hits the coast at an oblique angle
.The swash carries the material up the beach in the same direction as the waves
.The backwash then carries material down the beach at right angles towards the sea.
.Overtime material zigzags along the coast
How spits form
.Spits form at sharp bends in the coastline
.Longshore drift transports sand and shingle past the bend and deposits it in the sea
.Strong winds and waves can curve the end of the spit
.There is a sheltered area behind the spit which is protected from waves meaning it can support plant life
.Over time the sheltered area can become a mud flat or a salt marsh
How bars form
.A bar is formed when a spit joins 2 headland together
.The bar cuts off the bay between headlands from the sea.
.This means a lagoon can form behind the bar
Saltation
A hopping or bouncing motion of particles too heavy to be suspended
Traction
Large pebbles rolling along the sea bed
Why is the Holderness coastline at risk of erosion
.Cliffs are mainly made up of boulder clay which is weak
.Prevailing wind comes from the norweagian sea meaning waves increasing in power over a long distance eventually battering the cliff with excessive force
How rising sea levels increase risk of coastal flooding
Rising sea levels could expose more of the coastline to erosion-beaches would become narrower and sea will move inland. This also means higher and stronger tides forming destructive waves removing sediment from the beach
How storm frequency increase risk of coastal flooding
Storms give sea more erosional power. The sea will also have more energy to transport and remove sediment from beach leaving coasts naked.
Threats of coastal flooding to people
Low-lying coast areas may be permenantly flooded so they cannot be inhabited. Coastal industries may also shut down due to damage to equipment forcing people to lose jobs. Risk of damage to infrastructure
Threats of coastal flooding to the environment
Ecosystems will be affected because sea water has a high salt content. This can damage and kill organisms as well as ruin soil. Bars could be destroyed connecting lagoons to the sea
Hard engineering
Man made structures built to control the flow of the sea reducing flood and erosion
Soft Engineering
Schemes set up using knowledge of the sea at it’s processes to reduce affects of flooding and erosion
Types of Hard engineering
Sea Wall
Groynes
Types of soft engineering
Beach Replenishment
Slope stabilisation
Strategic realignment
Long Profile
Shows you how the gradient changes over different courses
Cross Profile
Shows you what the cross section of the river looks like
Upper Course
Steep Gradient. V-Shaped valley,steep sides,narrow and shallow channel
Middle Course
Medium Gradient. Gently Sloping valley,sides are wider and deeper channel
Lower Course
Gentle Gradient. Very wide,flat valley and a deep channel
Vertical Erosion
This deepens the river valley making it v shaped
Lateral Erosion
This widens the river valley
Upper Course of the River Eden
The source of Eden is 600 m above sea level in an area of hard resistant rock Steep Gradient River Channel is narrow and shallow Discharge is Low Velocity is Low
Middle Course of the River Eden
It is in an area of soft less resistant rock
Gradient of the channel is mildly steep
Discharge is mild
Sediment is made of of smaller rounder rocks
Lower Course of the River Eden
High Velocity
High Discharge
Material carried by the river is fine and well rounded
Material is carried around by suspension or solution
How weathering shapes river valleys
Via freeze thaw weathering
Solution
River water disolves some types of rocks such as limestone and chalk
Types of sediment transportation in rivers
Traction
Suspension
Saltation
Solution
Traction in rivers
Large particles like boulders being pushed along the river bed
Suspension
Small particles being carried along by the water
Saltation
Pebble sized particles bouncing along the river bed
Why do rivers slow down and deposit material
The volume of water in the river falls
The amount of eroded material in the water increases
The water is shallower
The river reaches the mouth
How a waterfall forms
Softer rock is eroded more than hard rocks creating a step
As the water goes over the step it erodes more softer rock
The steep drop is eventually created
How gorges form
The hard rock from the waterfall is eventually undercut by erosion. It becoms unsupported and collpases
The collapsed rock swirl around the foot of the waterl fall where they erode softer rock creating a deep plunge pool
Over time undercutting causes more collapses causing the waterfall to retreat creating a gorge
Interlocking spurs
Zip like landscapes caused by the river winding around them
Where are meanders often found
Middle and lower courses
How are meander formed
The current is faster than on the outside the bend.
Some more erosion takes place (hydraulic action and abrasion)on the outside of the bend forming river cliffs
The current is slower on the inside of the bend because the river channel is shallower
So eroded material is deposited on the inside of the bend forming slip off slopes
How are ox bow lakes formed
Erosion causes the outside bends to get closer until there is only small bit of land left between the bends (called the neck)
The river breaks through this land and the river flows along the shortest course
Deposition eventually cuts of the meander forming an ox bow lake
Flood Plains
Is a wide valley floor on either side of a river which occassionally gets flooded
What are levees
Natural Embankments along the edges of a river channel
How do levees form
During a flood eroded material is deposited over the whole flood plain. The heaviest material is depostied closest to the river channel because it gets dropped first when the river slows down. Over time material builds up creating levees along edges of the channel
What are deltas
Low lying areas where the river meets the sea or lake
Deposition forming Deltas
Rivers are forced to slow down when they meet sea or lake. This causes them to deposit material that theyre carrying. If the sea doesn’t wash away the material it builds up and the channel gets blocked. This forces the channel to split up over smaller rivers called distributaries.
How does climate shape river landscapes
Wetter climates mean higher discharge. Higher discharge increases rate of erosion. Higher volume of water means more sediment can be carried which causes abrasion.
How does geology shape river landscapes
River flowing theough areas of hard rock means lower rate of erosion and sediment load. Areas with soft rocks are easier to erode and have a higher sediment load. Areas with mire resistant rock have steeper sides whereas softer rocks have a gentle sloping valley side
Interlocking spurs
Form when softer rock is eroded first leaving hard rock sticking out
How do slope processes shape river landscapes
Vertical erosion makes valleys steeper increasing movement down slopes. Mass movement can add large amounts of sediment to rivers load. Soil creep causes soil to expand and contract the soil causing water to add weight to the soil and once dried adds fine material to sediment load
Peak Discharge
The highest discharge in the period of time
Lag time
The delay between peak rainfall and peak discharge
Rising limb
The increase in river discharge as rainwater flows into the river
Falling limb
The decrease in river discharge as the river returns to its normal level
What is river discharge measured in
Cumecs
Factors that affect storm hydrographs
Geology Soil type Slope Drainage Basin Type Antecedent conditions Urbanisation Deforestation
Physical factors that affect river Eden flooding
In the wettest parts of the UK with intense rainfall
It is bordered by Eden basin meaning rock is impermeable and can’t soak and runs into the river channel
Snowfall in winter months rapidly adds water to river
Human factors that affect river Eden flooding
Carlisle is built on the flood plain which affects absorbtion and water storage. As well as lack of vegetation means little infiltration
Natural woodland being cleared out causes increase runoff and decrease interception
Parts of eden have been drained to make them suitable for farming. Drainage ditches means water flows to river rapidly
Human and physical factors that led to flooding in river eden
Antecedent conditions Heavy rainfall Short lag time Blockages and Debris Insufficient drainage
Main factors causing river flooding in the UK
Increased frequency of storms causing rainfall to become more intense and more saturated ground increasing likelihood of flooding.
Land use change caused deforestation of lands reducing interception and increasing flood risk as well as urbanisation causing building on flood plains making the area prone to flooding
Flooding threats to people
Injury and casualties
Floodwater is contaminated with sewage causing diseases
Possessions can be damaged and washed away
Loss of job,businesses and homes
Flooding threats to environment
Floodwater can be contaminated with sewage which can pollute land and destroy habitats
Farmland can be damaged by silt and sediment load
River banks eroded can causes huge change to river landscape
Flood walls
Artificial barriers built along river banks. Designed to increase height of river banks allowing river to hold more water
Enbankments
High banks built along the the river bank and stop the river flowing into built up areas during a flood to protect buildings and incrastructure
Flood barriers
Built on river estuaries to stop flooding from storm surges or high tides
Flood barriers
Demountable flood barriers provide temorary protection against flooding. Barriers put up as a risk to the flooding forecast
Flood plain retention
Involves maintaining the river flood plain by not building on it and allows floodplain to do its job
River restoration
Involves making the river more natural so that the flood plain floods naturally
