Section C - Physical Landscapes In The Uk Flashcards
How is rock breaken down
Mechanical and chemical weathering
What is mechanical weathering
breakdown of rock without changing its chemical composition
What is chemical weathering
Breakdown of rock by changing its chemical composition
What is mass movement
When material falls down a slope
What waves erode the coast
Destructive waves
What waves deposit material
Constructive waves
What are the characteristics of destructive waves
High frequency and are high and steep
Their backwash is more powerful than their swash so material is moved
What are the characteristics of constructive waves
Low frequency and are low and long
Their awash is more powerful than their backwash, so material is deposited
Waves wear away the coast by using three processes erosion, what are they?
Hydraulic action
Abrasion
Attrition
How is material transported along the coast
Longshore drift
How is longshore drift done
1.Waves follow direction of prevailing wind
2.they hit coast at an oblique angle
3.swash carries material up the beach, in same direction as waves
4.backwash then carries material down the beach at right angles, back towards the sea.
5.overtime, material zigzags along coast
What are the four other processes of transportation
Traction
Saltation
Solution
Suspension
What is deposition
The dropping of material
What are concordant coastlines
The alternating bands of hard and soft rock are parallel to the coast
What are discordant coastlines
Are made up of alternating bands of hard and soft rock at right angles to the coast
Where are headlands and bays formed
Along discordant coastlines
Headlands are eroded to form caves,arches and stacks. How is this process done?
1.resistant rock that makes up headlands often has weaknesses like cracks
2.waves crash into headlands and enlarge the cracks mainly by hydraulic action and abrasion
3.repeated erosion and enlargement of the cracks causes a cave to form
4.continued erosion deepens cave until it breaks though the headland to form an arch
5.erosion continues to wear away the rock supporting arch, until it eventually collapses -this forms a stack
How are wave-cut platforms formed
1.waves cause erosion at the foot of a cliff - forming wave-cut notch
2.repeated erosion causes rock above the notch to eventually collapse
3.collapsed material washed away - new wave-cut notch starts to form
4.after repeated collapses, cliff retreats - leaving wave-cut platform
Where are beaches found and how are they formed
They are found between the high and low water marks
Formed by constructive waves
What is an example of hard-engineering strategies for coastal landforms
Sea wall
Gabions
Rock armour
Groynes
What is an example of soft engineering strategies for coastal landforms
Beach nourishment
Dune regeneration
What is another option that helps defend coastal landforms
Managed retreat
What are the characteristics of the upper course of a river
Gradient = steep
V-shaped valley, steep sides
Narrow, shallow channel
What are the characteristics of the middle course of the river
Gradient = medium
Gently sloping valley sides
Very wide, deep channel
What are the characteristics of the lower course of the river
Gradient = gentle
Very wide, almost flat valley
Very wide, deep channel
There are two types of erosion which change the cross profile of river, what are they and explain them
Vertical erosion - deepens the river valley and channel - dominant in upper course of river
Lateral erosion - widens river valley and channel - dominant in middle and lower courses of river
What are the four processes of erosion
Hydraulic action
Abrasion
Attrition
Solution
What are the four transportation
Traction
Suspension
solution
Saltation
How are waterfalls formed
1.When a river flows over an area of hard rock followed by an area of soft rock
2.softer rock is eroded by hydraulic action and abrasion more than the hard rock creating a step in the river
3.as water flows over the step it erodes more and more of the softer rock
4.a steep drop ie eventually created- called a waterfall
How are gorges formed
1.Hard rock is eventually undercut by erosion / eventually collapses
2.collapsed rock swirled around foot of waterfall where they erode the softer rock by abrasion - creates a deep plunge pool
- More undercutting and collapses, eventually cause waterfall to retreat leaving behind a steep-sided gorge
Where are gorges and waterfalls found
Upper course of a river
Where are meanders found
In the middle and lower courses of a river
What are the characteristics of a meander
Current is faster on outside of the bend as channel is deeper
More erosion takes place on outside of the bend, forming river cliffs
Current slower on the inside of bend because river channel shallower
Eroded material is deposited in inside of bend, forming slip-off slopes
How are oxbow lakes formed
By meanders
Give the steps of how oxbow lakes are formed
1.erosion causes outside bends to get closer
2.until there’s only a small bit of land left between the bends
3.river breaks through and his land
4.and river flows along shortest course
5.deposition eventually cuts off meander - forming oxbow lake
What are physical factors that affect flood risk
Heavy rainfall
Prolonged rainfall
Geology
Relief
What are human factors that affect flood risk
Land use
Give examples of hard engineering strategies that can reduce the risk of flooding
Dams and reservoirs
Channel straightening
Embankments
Flood relief channels
Give examples of soft engineering strategies that can reduce the effects of flooding
Flood warnings and preparation
Flood plain zoning
Planting trees
River restoration
