UKs Evolving Landscapes Flashcards
How are igneous rocks formed
They are formed by magma from the molten interior of the earth.
When magma erupts it cools inside the earth which forms igneous rock
How is a sedimentary rock formed
Formed from sediments that have settled at the bottom of the lake, sea or ocean
Have been compressed over millions of years
How is a meta morphic rock formed
They are formed by a rock being put under immense amounts of heat and pressure causing them to change into a metamorphic rock
2 types of igneous rock and characteristics
Granite
Basalt
Impermeable
Very resistant to erosion
type of metamorphic rocks and characteristics
Slate
Very resistant
Impermeable
2 types of sedimentary rock and characteristics
Chalk
Clay
Permeable
What is freeze thaw weathering
1.Water enters the rock
2.water freezes and expands widening the crack (below 0)
3 the ice melts water goes deeper into crack
4 process is repeated until rock splits
What is biological weathering
Plants and animals effecting rocks. Roots burrow down weakening the structure if the rock until it breaks away
Explain one type of biological weathering
1 Plants roots get into smalls cracks in the rock
2 As the roots grow the cracks become larger
2 This causes small pieces of rock to break down
What is chemical weathering
Rainwater and sea water contain weak acids
Over time the acids dissolve weak rock such as limestone or chalk
What are sea walls
Concrete walls placed at the foot of the cliff to prevent erosion. They are curved so they reflect the energy back into the sea
What is rock armour
Large boulders placed at the foor of the cliff. They break the waves and absorb their energy
What are gabions
Rocks which are held in mesh cages and placed in area affected by erosion
What are groynes
Wooden or rock structures built at right angles into the sea
What is beach replenishment
Sand and shingle from the sea bed is moved towards the beach
What is beach reprofiling
Reshaping the beach using existing beach material
What is dune regeneration
Grass planted in sand dunes to stabilise the dunes and helps to trap sand to build them up
What is dune fencing
Fences are built on the sandy beaches, which encourage new dunes to form
Advantages and disadvantages of sea walls
Very effective
Very long lasting
Very expensive £2000 per metre
Very ugly
Advantage and disadvantage of groynes
Not to expensive
Builds up beaches
Starves the beack further down the coast line of sediment
Look unattractive
Advantage and disadvantage of gabions
Cheap and easy to mantain £100 per metre
Absorbs wave energy
Not very strong
Looks unatural
Advantages and disadvantages of rock armour
Relatively easy to maintain
Effective at reducing wave energy
Can beshifted if the rock is too small
Expensive to transport
Advantages and disadvantages of beach nourishment
Blends in with the existing beach
Creates wider beaches
Can kill or destroy animal habitats
Expensive and has to be repeated
What are the advantages and disadvantages of beach reprofiling
Provides an effective buffer for the coastline
Looks reasonably natural
Can be expensive
Has to be done regularly
What are the advantages and disadvantages of dune regeneration
Wave energy is absorbed
It is cheap
The protection is limited to a small area
Can be damaged by storms or waves
What are the advantages and disadvantages of dune fencing
Constructed out of natural material
Have minimal minimal impact on natural systems
Can be damaged by storms
Needs maintenance
What is a concordant coastline
A concordant coastline has the same type of rock along its length
What is a discordant coastline
A discordant coastline has two types of rock soft and hard bays and headlands form here
How does a cove form
1.For a cove to form hard and soft rock must alternate
2. The hard rock cliff may suddenly crack as erosion weakens a section of the cliffs
3. Overtime The hard-rock erodes to expose a less resistant rock behind it
4. The less resistant rock erodes much quicker so the Cove widens more in the soft rock band
5. Erosion continues to widen the Cove but cannot extend further inland due to another band of hard Rock
6. Finally waves defect as they passed to the Coves opening
What is a headland and a bay
A bay is it inlet of sea where The land curves inwards usually with a beach
a headland is another piece of land that projects from a coastline into a sea
What is hydraulic action
An emotional process in which the wave hits the cliff using shear force to erode it 
What is abrasion
Erosional processes in which pieces of sediment are thrown at a cliff By a wave
What is attrition
Wave action causes rocks and pebbles to hit each other wearing each other down to become around in smaller
What is corrosion/solution
Seawater in the rain water contain weak acids overtime rocks and cliffs are eroded by it
Caves, arches, stacks and stumps formation
The cave wide and deep and due to both marine erosion and sub aerial processes and eventually a large hole will form through the other side of the headland
this is known as an arch the arch continues to widen until it is unable to support itself the top falls due to its own weight through mass movement
this leaves a stack as one side of the arch becomes detached from the mainland
With marine erosion attacking the base of the stack eventually the stack will collapse into a stump
What is marine erosion.
The wearing away and breaking up of a rock along the coast
Describe the process of longshore drift
Waves approach the coast at an angle
Swash Carrys sediment up the beach at an angle
Backwash carry sediment down the beach with gravity at a right angle to the sea
This creates a zigzag movement of sediment along the beach
How does a wave cut notch and platform form
- The sea attacks the base of the cliff between high and low tides
- A wave cut not is formed by a erosional processes such as abrasion and hydraulic action
- As the notch increases in size the cliff becomes unstable and collapses leading to the retreat of the cliff face
4.The backwash carries away eroded material, leaving a wave cut platform
- The process repeats which makes the cliff continue to retreat
What is sub aerial processes
The processes of weathering and mass movement
Constructive waves characteristics
These waves are are low in height and have limited energy
They have a strong swash but weak backwash
They tend to build the beaches by depositing sediments
Destructive wave characteristics
These waves are high powerful waves
Have a weeks wash but strong backwash
They erode the coastline by removing material from beaches and cliffs
How do waves form
Waves are created by winds as they blow over the sea
Shallow water near the coast causes friction with the seabed
The top of the water is travelling faster so it starts to tip forward
The wave then topples forward or breaks
What is solution
Chemicals are dissolved into the sea water
What is suspension
Particles and smaller rocks are light enough to float within the waves
What is traction
Large rocks rolled along the seabed
What is Saltation
Pebbles or small rocks that are too heavy to be suspended bounce along the seabed
How to spits form
Spits are formed due to deposition
Longshore drift occurs along the coastline but as the wave lose energy the deposit the sediment
Normally due to going into a sheltered area such as behind the headland or a mouth/estuary
The deposit of sediment overtime this creates a spit
What are rockfalls
Occur on sloped cliffs when the rock becomes exposed to mechanical weathering often Freeze thaw which causes rocks to roll down a cliff
What are landslides
Water between sheets of rock and the rock face reduces friction and allows large chunk of rock to slide down the cliff
What are mudflows
Saturated soil flows down the face of a hill like a fluid bulging at the bottom in a lobe
What are rotational slips
Also known as slumps, soil and rock fragments become saturated with water however instead of sprawling down the hill like a mudflow chunks of rock and soil slip creating stepped heads down the cliff face
What is a wave cut notch
A dent in the cliff usually at he level of high tide
Describe the upper course
The upper course as many tributaries which are narrow and. V-shaped
Each tributary doesn’t carry a lot of water but combined the tributaries all fill up the river channel further down
The sides of the tributaries tend to be like a valley With a large gradient either side so water run into the tributary
Describe the middle course
The tributaries merge together to form a channel, which is rounder in shape and deeper, to adjust to the increase in water
The more water that passes by, the larger the energy of the water of the water which leads to more erosion to take place to widen the channel The area around the river channel isflat and low-lying,which is the floodplain if the river needs to flood.
Describe the lower course
The lower course Carries the largest volume of water it is in a very wide and very deep channel
There are ridges either side of the river banks called levees
this size of the valley has increased so it is even wider and flatter than the middle course
Interlocking spurs
Interlocking spurs are found in the upper course of the river where the water doesn’t have a lot of energy so it isn’t very powerful
the low energy means the water isn’t strong enough to erode resistant rocks, instead the river rerouting curls around them
Describe the lower course
The lower course carries the largest volume of water in a very wide and very deep channel.
There are ridges either side of the river banks called leeves
Solution in rivers
Chemicals dissolved in the river water
Suspension in rivers
Particles and small rocks are light enough to float within water
Saltation in rivers
Pebbles and small rocks are to heavy to be suspended , bounce along the river channel
Traction in rivers
Large rocks are rolled along the river bed
What is deposition in rivers
Deposition is the dropping of the rivers load when the water in a river decreases in speed
If the River Travels slower, the water has less energy and can carry less material
River land forms in the upper course
Waterfalls
Interlocking spurs
V shaped valley
River land forms in the middle course
Gorges
Meanders
River land forms in the lower course
Flood plains
Ox bow lake
River estuary
How do water falls form
In an area where a river flows
over an area of hard rock and
soft rock, the soft rock erodes
more quickly.
The soft rock erodes away from the hard rock over time creating a step
The soft rock continues to erode undercutting the hard rock The hard rock is left suspended in the air as an overhang
Due to the force of gravity the unsupported overhang collapses on the broken up rocks fall into the plunge pool which acts as tools for erosion and further deep into the plunge pool
Erosion continues to undercut underneath the hard rock creating overhang again further upstream
The continual process of the overhang collapsing causes the waterfall to retreat upstream
What are gorges
Gorgeous form from water falls as the waterfall retreats upstream it leaves behind A steep valley carved into the rock with a river running along the base
How do meanders form
Water travels faster on the outside of the bend which means lateral erosion
On the opposite side the water travels slowly and changes direction sharply until the water loses energy and deposit sediment
Which river landforms are found in the upper course
-Waterfalls
-Interlocking spurs
-V shaped valley
Which river land forms are found in the middle course
-Gorges
-Meanders
Which river land forms are found in the middle course
-Flood plains
-Ox bow lake
-River estuary
