The UK's Evolving Physical Landscape Flashcards
What is a landscape
The character of an area, resulting from the action and interaction of natural and human elements
What is igneous rock
Form when magma from the mantle cools down and hardens
As it cools, crystals form in the rock
Igneous rocks are hard and more resistant to erosion
What is sedimentary rock
Layers of sediment are compacted together until they become solid rock
What is metamorphic rock
When rock (igneous, sedimentary or older metamorphic rock) is put under pressure and heat (but not melted), the original rock becomes a new type of rock
This new rock becomes harder and more compact
Stronger, more resistant rocks tend to produce …
Highland areas
Weaker rocks tend to form …
Lowlands
What are the characteristics of igneous rock
Hard
Resistant
Impermeable
Upland
What are the characteristics of metamorphic rock
Very hard
Very resistant
Impermeable
Upland
What are the characteristics of sedimentary rock
very soft
Less resistant
Permeable
Lowland
What is weathering
breakdown of rock in their original place
What is mass movement
weathered material moving down slopes under the influence of gravity
How has the landscape been changed
Settlements
Agriculture
Forestry
What are concordant coastlines
made up of the same rock type, running parallel to the sea, these coastlines produce coves
What are Discordant coastlines
have alternating bands of rock perpendicular to the sea, these types of coastlines form headlands and bays
What are the types of erosion
Hydraulic action
Attrition
Corrosion
Abrasion
What is hydraulic action
The sheer force of the waves hitting the coast
What is Attrition
Material (rocks, shingle, etc.) are carried by the waves and bump against each other and are worn smaller and smoother
What is corrosion
slightly acidic and this gradually dissolves some types of coastal rock
What is abrasion
Abrasion (or corrasion) - waves pick up material and hurl it at the coast
How are headlands formed
Occur where there are alternating bands of hard and soft rocks run perpendicular to oncoming waves (discordant coastline)
At first, the soft rock (e.g. clay) is eroded backward, forming an inlet
How are bays formed
As the inlet continues to erode it curves inwards, and a bay is formed, usually with a beach
How are cliffs formed
Cliffs are shaped through erosion and weathering processes
How are wave cut platforms formed
As the sea attacks the base of a cliff between the high and low water mark, a wave-cut notch is formed
Abrasion, corrosion and hydraulic action further extend the notch back into the cliff
The undercutting of the cliff leads to instability and collapse of the cliff
The backwash of the waves, carries away the eroded material, leaving behind a wave-cut platform
How do caves,arches,stacks and stumps form
What are the factors that determine the height and strength of waves
The fetch
The amount of time wind blows
The strength of the wind
The movement of water up the beach is called the …
Swash
The movement of water down the beach is called the
Backwash
What are destructive waves
waves erode the beach
What are constructive waves
waves are beach builders
What is mechanical weathering
Water gets into cracks and joints in the rock
When the water freezes it expands and the cracks open a little wider
When the water thaws, the crack contracts, releasing pressure on the crack
Over time, repeated freezing and thawing, widens the crack until pieces of rock split off
What is chemical weathering
occurs when rocks are broken down by a chemical process
What is biological weathering
takes place when rocks are worn away by living organisms
What is traction
where large heavy material is dragged along the sea floor
What is saltation
where smaller material is bounced along the sea floor
What is suspension
where fine material is held in the water
What is solution
dissolved material is carried in the water
What is longshore drift
Influenced by the prevailing wind, waves approach the beach at an angle
As the waves break, the swash carries material up the beach at the same angle
As the swash dies away, the backwash carries the material down the beach at right angles (90°)
The process repeats, transporting material along the beach in a zig-zag movement
What is a spit
An extended stretch of sand that extends out to sea from the shore
How are spits formed
Sediment is transported by the action of longshore drift
Where the coastline changes direction, a shallow, sheltered area allows for the deposition of sediment
Due to increased friction, more deposition occurs
Eventually, a spit slowly builds up to sea level and extends in length
If the wind changes direction, then the wave pattern alters and results in a hooked end
The area behind the spit becomes sheltered
What are the human activities that take place on the coast
Development
Agriculture
Industry
Coastal management
How can coastal flooding be caused
Storm surges
Storm tides
Tsunamis
What is hard engineering
involves building some form of sea defence, usually from concrete, wood or rock
What is soft engineering
works with natural processes rather than against them
What are the characteristics of the upper course
Shallow
Steep valley sides
Narrow
Low velocity
Vertical erosion
What are the characteristics of the middle course
Deeper than upper course channel
Gentle valley sides
Wider than upper course channel
Greater velocity than upper course
Lateral erosion
What are the characteristics of the lower course
Deeper than middle course channel
Wider than middle course channel
Greater velocity than the middle course channel
Deposition is dominant
What is deposition
when a river does not have enough energy to carry its material and it drops it
How are waterfalls formed
The soft rock erodes quicker, undercutting the hard rock and creating a plunge pool
This leads to the development of an overhang of hard rock which eventually over time, collapses
The overhang falls into the plunge pool increasing abrasion and making the plunge pool deeper
The process then begins again and the waterfall retreats upstream leaving a steep sided gorge
How are V shaped valley’s formed
Vertical erosion is dominant in the upper course of the river
This cuts down into the river bed and deepens the river channel
Weathering and mass movement leads to material from the valley sides collapsing into the river forming a steep v-shaped valley
How are meanders formed
The fastest water flow is on the outside of the river bends, leading to erosion:
The erosion undercuts the river bank forming a river cliff
The river bank collapses and the edge of the meander moves further out
How are oxbow lakes formed
The erosion on outside bends can eventually lead to the formation of a meander neck
At a time of flood, the river may cut through the neck of the meander forming a straighter course for the water
The flow of water at entry and exit from the meander will be slower, leading to deposition
The meander becomes cut off from the main river channel, forming an oxbow lake
What are levees
The heaviest material is deposited first nearest to the river channel forming natural embankments called levees
What is lag time
The time difference between the peak rainfall and peak discharge
What are the factors that cause high and low flood risk
What are the impacts of flooding
