Topic 4: UK Physical Flashcards
How are Igneous rocks formed?
They are created by volcanic activity when magma or lava cools, forming rocks made of crystals that are usually hard.
How are Sedimentary rocks formed?
Are formed of small particles that have been eroded, transported, and deposited in layers, or from the remains of plants and animals.
What are Metamorphic rocks?
They are existing rocks that have been changed by extreme pressure or heat. They are usually comprised of layers or bands of crystals and are very hard.
Identify the weathering type, slope processes and post glacial river processes in upland areas.
Freeze that weathering
Dry valleys
Soil creep
Identify the weathering types, slope processes and post glacial processes in low land areas.
Chemical weathering
Biological weathering
Dry valleys
Soil creep
What are the characteristics of a destructive wave?
Strong backwash
Tall wave height
Which of these describes the fetch?
The distance that the wind has to blow over water
Waves crash against rock and compress the air into the cracks. Thos puts pressure on the rock. This happens over and over again until rock breaks off describes.
What is this?
Hydraulic action / power
Eroded particles in the water smash into each other and break into smaller fragments. Their edges also get rounded off as they rub together.
What is this?
Attrition
Eroded particles in the water scape and rub against rock, removing small bits.
What is this?
Abrasion
When water gets trapped between sand and clay along a coastlines the subaerial process of mass movement occurs.
True or False?
True
Freeze thaw weathering is an examples of mechanical weathering.
True or False?
True
What best describes discordant coastlines?
Different rock types
Headland and bays a common feature
Longshore drift moves up the beach in a straight line and travels down the beach in the direction of the prevailing wind.
True or False?
False
What is the landform for deposition?
Spit
Glacial processes ______ years ago the uplands were under ___m of ice with eroded large corries like Blea Water.
a. 12,000
b. 300m
As ice moved through the upland landscape it eroded juge areas to create _-______ ______. These had steep sides, flat bottoms and hanging valleys.
U-shaped valley
Name the 3 types of weathering
Biological, Chemical, Freeze-thaw
Name the 4 erosion methods
Abrasion
Attrition
Hydraulic Action
Solution
What is Chemical Weathering?
When chemicals break down rock as a result of a chemical reaction.
During glacial periods (when the climate was colder) the gaps in the chalk froze making it ___________. When seasonal snow melt occurred, it couldn’t infilitrate into the chalk and instead ran over the top and ______ the valleys. Now (it is warmer amd the ground has melted) the water runs underground through the chalk and the rivers can’t be seen.
a. Impermeable
b. Eroded
What is soil creep?
Soil creep is the slowest of all mass movements. It takes place at a rate of 1-3mm per year in temperature latitudes and 10mm per year in tropical forests.
Soils such as _________ and clay can absorb large amounts of ________ and become saturated - they can move down the slope
a. Sandstone
b. Moisture
The UK climate is very ___. Heavy rain can lead to ________. When rivers foood the overflowing water carries sediment and deposits silt on the valley floor forming a flood plain. The floodplain is very fertile. This is important in the lowland areas however in the upland areas the river is eording downwards carving out a V-shape valley.
a. Wet
b. Flooding
What is weathering?
The breakdown of rock into smaller pieces
What is erosion?
The wearing away of rock. During the last glacial period, ice eroded the landscape. Rivers amd the sea now constantly erode the landscape.
What are 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 it melted.
What do Groynes do?
Groynes work to stop longshore drift transporting sediment along the coast amd instead encourage deposition of sediment on beaches. As the beach gets bigger it will be able to absorb wave energy and protect the coadt.
Identify a negative of sea walls.
Really expensive
How does Beach mourishment reduce erosion?
Adding sediment to a beach builds up the beach height.
How does slope stabilisation reduce erosion?
Drainage channels are built and vegetation improved
How does the sea wall reduce erosion?
Reflects the wave of energy
How do groynes reduce erosion?
Traps sediment
Benefits of groynes?
Prevents longshore drig moving beach material along the coast
Benefits of sea walls?
Protects cliffs, buildings from erosion
Benefits of beach nourishment?
Helps reduce the threat of back shore erosion
What are the upper course landforms?
Waterfalls
V-shapes valleys and interlocking spurs
What are the middle course landforms?
Meanders
Oxbow lake
What are the lower course landorms
Floodplain
Levee
Delta
What is a meander?
A series of curves throught the middle course of a river.
What is an oxbow lake?
A river in a U-shape
What is the river course?
The path of a river as it flows downhill.
What is the upper course?
Closest to the source
What is the middle course?
Middle part of the river
What is the lower course?
Closest to the mouth
What is the river valley?
Rivers form channels and valleys as they flow downhill
What is the long profile?
Shows you the gradient (steepness)
What is the cross profile?
The cross section of the river
What is discharge?
The volume of water flowing in a river measured in m(3)/sec or cumecs
Does river discharge increase or decrease?
Decrease
Does the channel width increase or decrease?
Increase
Does the channel depth increase or decrease?
Increase
Does the velocity increase or decrease?
Increase
Does the sediment load size increase or decrease?
Decrease
Does the sediment particle shape increase or decrease?
Decrease
Does the gradient increase or decrease?
Increase
What are ox-bow lakes formed from?
Meanders
What are meanders formed by?
Erosion and deposition
What is lag time?
Difference between peak rainfall and peak discharge
What is the rising limb?
Shows rising water after rainfall
What is the falling limb?
Shows discharge falling as less water reaches the channel
What is the ground water flow?
Water level flowing under the surface
What human factors affect storm hydrographs
Drainage systems
Deforestation
Urbanisation
What physical factors affect storm hydrographs
Vegeatation
Topography
Rock type
Heavy storms
Describe the location of the river Eden
North west England
On the Scottish border
West of Lake District in Cumbria
Physical factors increasing chance of flooding
Wet antecedent conditions
Human factors increasing chance of flooding
Drainage ditches being dug in the drainage basin
What are Embankments? Give one advantage and disadvantage
Embankments are high banks that are built slong or near the river banks
A: They stop water from spreading areas where it could cause problems, such as in settlements
D: Flood water may go over the top, then get trapped behind them
What are flood walls? Give one advantage and disadvantage
Flood walls are artificial harriers built along river hanks
A: They prevent water from spreading into areas of high impact (housing)
D: Expensive to build
How are wave cut platforms formed?
Waves cause most erosion at the foot of a cliff
This forms a wave cut notch, enlarged as erosion continues
The rock above the notch becomes unstable and eventually collapses
Collapsed material is washed away and a new wave cut notch starts to form
Repeated collapsing results in the cliff retreating
A wave cut platform is what’s left behind
How do headlands erode to form caves, arches and stacks?
Headlands are usually made of resistant rocks that have weaknesses like cracks
Waves crash into the headlands and enlarge the cracks - mainly by hydraulic power and abrasion
Repeated erosion and enlargement of the cracks causes a cave to form
Continued erosion deepens the cave until it breaks through the headland
Erosion continues to wear away the rock supporting the arch, until it eventually collapses
This forms a stack - an isolated rock that’s separate from the headland