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