The UK's Evolving Physical Landscape Flashcards
How did geology influence the physical landscape of the UK?
- 250m-300m years ago, the UK was covered by tropical seas.
- Calcium carbonate crystallised around the fragments and cemented them together.
- Later other rocks strata were deposited on top of the limestone
- As the fish died, skeleton would fall and compact beneath into rock.
How did glaciation influence the physical landscape of the UK?
- As the Pennines eroded, rivers eroded into them created v-shaped valleys.
- Altering river valleys, making them deeper and wider making them u-shaped troughs.
- As they melted the glaciers left features.
How did tectonic processed influence the physical landscape of the UK?
- When uplift, rocks snap and move along faults in a series of earthquakes.
- Convection currents beneath tectonics uplifted rocks from below the sea which created land.
- 3 major tectonic process over 300m years.
- Each movement which happened disturbed the strata causing the rocks to tilt.
- Uplift can raise more parts than others.
What are the features of an igneous rock?
- Formed by the cooling and solidification of magma/molten.
- Formed beneath the Earth’s surface or on its own as lava.
What are the features of a sedimentary rock?
- Formed through deposition and solidification of sediment.
- Most commonly found in water.
- Sometimes contain fossils.
What are the features of a metamorphic rock?
- Been changed by extreme heat and pressure causing the rock to have physical or chemical change.
Features of chalk.
- Purer, younger form of limestone.
- Very porous.
- Sedimentary
Features of limestone.
- Permeable.
- Consists pf crushed corals that were formed in tropical seas.
- Sedimentary.
Features of clay.
- Formed from muds.
- Soft and crumbly.
- Very weak.
- Found near rivers or sea.
- Sedimentary.
Features of granite.
- Formed from cooling magma.
- Contains glass crystals, white and skinny black crystals.
- Very resistant
- Igneous.
Features of schist.
- Formed by further metamorphic of slate when it is partly melted and solidified.
- Very resistant.
- Metamorphic.
Features of slate.
- Formed from heated muds or shale.
- Could be sedimentary.
- Very resistant.
- Metamorphic.
Features of an upland area in the UK - Snowdonia.
- Igneous rock.
- Slates and shales.
- 600m years.
- Very resistant.
- Heavy relief.
- Black and heavy rocks.
Features of a lowland area in the UK - London.
- Sedimentary.
- Sands and clays.
- 70million.
- Weak resistance.
- Relief becomes shale.
- Soft and crumbly rock.
How have active volcanoes shaped the land - tectonic process?
- 520M years ago the land that the UK is on now was closer to a plate boundary than now.
- Forced magma through the crust which cooled to from igneous rocks.
How have plate collisions shaped the land - tectonic process?
- Caused rocks to be folded and uplifted forming mountain ranges - these are now probably uplands.
- Intense heat and pressure formed metamorphic rocks.
How have plate movements shaped the land - tectonic process?
- 345-280M Britain was in the tropics.
- Higher sea levels meant it was underwater.
- Carboniferous limestone formed in warm shallow seas which can now be seen in uplands of peak district.
When the UK was covered in mostly ice, how did it happen over this 2.6M period?
- Very powerful meant it was able to erode the landscape carving out u-shaped valleys in upland areas.
- Glaciers deposited lots of materials as they melted.
- Landscapes formed by glacial melt water and deposits extend south of the ice sheets.
How did weathering alter the landscape?
- Breakdown of rock into smaller pieces.
- Mechanical, chemical and biological.
How did erosion alter the landscape?
- Wears away rock.
- During last glacial period, ice eroded the landscape.
- Rivers and sea now constantly erode the landscape.
How did post-glacial and river processes alter the landscape?
- Melting ice at the end of glacial periods made rivers bigger than normal with more power to erode.
- Ice left distinctive landforms when it melted, for example, hanging valleys.
How did slope processes erode the landscape?
- Include mass movements - rock falls, slides, slumps and soil creeps.
How are physical processes affected?
- By climate.
- Cold climate increases the chance of freeze-thaw weathering.
- Wet climate affects the number of streams and rivers.
What are the features of a u-shaped valley in an upland area? - Snowdonia
- Eroded by ice.
- Flat floor and steep sides.
- Contains a misfit river that looks too small to have created it.
How is a tarn formed in a upland area? - Snowdonia
- Sits in a corrie, therefore, it was hollowed out by ice in glacial times.
Where does freeze-thaw weathering occur in the corrie in an upland area? - Snowdonia
- Steep back wall.
- Rocks are broken up and rock falls which forms scree slopes.
How does the weather affect snowdonia?
- Most rocks are impermeable when there is lots of rain so lots of streams that are eroding the sides of the corrie and forming gullies.
What are rivers like in lowland areas?- The Weald
- Meander on impermeable clay, widening the valley floor -
How can climate affect the Weald?
- Due to wet climate heavy rain can lead to flooding.
- Overflowing river deposits slit on valley floor forming a flood plain.
What are dry valleys in lowland areas - The Weald?
- Valleys with no streams visible, streams flow underground in permeable chalk.
- Formed during glacial periods when the colder climate led to freeze-thaw weathering and glacial snow melt meant streams had much more water in them than they do today.
How have humans changed the landscape through agriculture?
- People have cleared the land to make space for farming. - Overtime hedgerows and walls have been put in to mark the fields.
What is an arable landscape best for in farming terms?
- Flat land with good soil is used for growing crops.
What is a dairy landscape good for in farming terms?
- Warm, wet areas are good as theres lots of large greasy fields.
What is a sheep landscape good for in farming terms?
- Harsher conditions in Uplands.
- Lack of trees in hills.
- Young trees are eaten or trampled before they get a chance to be matured.
How has human forestry changed the landscape?
- Management of woodland areas, used for timber, recreation or conservation.
- UK used to be covered un deciduous woodland but there is very little natural woodland left.
- Coniferous forests have been planted for timber, trees are often planted in straight lines. They don’t look natural. When areas are felled the landscape is left bare.
- In some places deciduous woodland is being replanted to try to return the area to a more natural state.
- OS maps show forestry plantations and areas that are bing managed.
How has human settlement changed the landscape?
- Settlers needed water supply so they needed somewhere that could easily be defended or that was sheltered from wind and rain.
- Bridging points over rivers and the availability of resources.
- Most of the biggest cities are ports and industrial areas.
- Look for buildings, railways, canals and embankments to identify settlements on OS maps.
As settlements grew, how did they affect the landscape?
- Land was concurred over roads and buildings which affected drainage patterns.
- Some rivers were diverted through underground channels.
- Some river channels were straightened or had embankments built to prevent flooding.
What are the features of mechanical weathering?
- Breakdown of rock without changing its chemical composition.
- Salt weathering affects coasts.
1. Seawater gets into rock cracks.
2. When water evaporates, salt crystals form. Salt crystals form and expand which puts pressure on the rock.
3. Repeated evaporation of saltwater and forming of salt crystals widens the cracks and causes there rock to break up.
What are the features of chemical weathering?
- Breakdown of rock by changing its chemical composition.
- Carbonation weathering is a type and happens in wet and warm conditions
1. Seawater and rainwater have CO2 dissolved in them, making them weak carbonic acids.
2. Carbonic acids react with rock that contains calcium carbonate so the rocks are dissolved by rainwater.
What are the features of biological weathering?
- Breakdown of rock by living things.
- Plant roots break down rocks by growing into cracks on their surface and pushing them a part.
What are mass movements and when and how do they occur?
- Shifting of rocks and loose material down a slope. It happens when the force of gravity acting on s slope is greater than the force supporting it.
- Cause coasts to retreat rapidly.
- More likely to happen when material is full of water acting as a lubricant which makes the material heavier.
What are the 3 types of mass movements and what do they do?
- Slides: material shifts in a straight line.
- Slumps: Material shifts with a rotation. (Rotational slumping.
- Rockfalls: Material breaks up and falls down slope.
How does hydraulic power erode the coast?
- Waves crash against the rock and compress the air in the cracks.
- Pressure is put on the rock.
- Repeated compression widens the cracks and makes bits of the rock break off.
How does abrasion erode the coast?
- Eroded particles in the water scrape and rub against the rock, removing small pieces.
How does attrition erode the coast?
- Eroded particels in the water smash into each other and break into smaller fragments. Their edges also get rounded off as they rub together.
How can the geological structure of a coastline influence the formation of erosional landforms?
- Hard rocks are more resistant so it takes longer for them to be eroded and weathered by physical processes.
- Softer rocks are less resistant which means they are eroded more quickly.
What are the features of discordant coastlines?
- Made up of alternating bands of hard and soft rock that are perpendicular to the coast.
- Bays and headlands are more common here because the bands of rocks are being eroded at different rates.
What are the features of concordant coastlines.
- Alternating bands of hard and soft rock are parallel to the coast.
- Eroded at the same time so there are fewer erosional landforms.
How does the UK’s climate have an impact on coastal erosion and retreat?
- Temperature varies with the seasons; coldest in winter, warm through spring, hottest in summer and cool through autumn.
- Differences in temperature have an impact on processes along get coast, for example, salt weathering because water evaporates more quickly.
- Storms are very frequent, especially in winter. Strong winds give high energy, destructive waves increase Erin of cliffs. Intense rainfall can cause cliffs to become saturated creating mass movements.
- Prevailing winds in the UK are mostly warm south westerlies which bring storms from the Atlantic Ocean.
- Cold northerly winds are common.
How do destructive waves wear away the coast?
- High, steel and have a high frequency, 10-14 waves per minute.
- Backwash, movement of water back down the beach, is more powerful than its swash, movement of water up the beach means material is removed from the coast.
- Storms increase erosional power which can lead to increased rates of coastal retreat.
How are wave-cut platforms formed?
- Waves cause most erosion at the foot of the cliff.
- Forms a wave cut notch, which is enlarged as erosion continues.
- Rock above the notch becomes unstable and collapses.
- Collapsed material is washed away and a new wave cut notch starts to form.
- Repeated collapsing results in the cliff retreating.
How do headlands and bays form along a discordant coastline?
- Soft rocks or rocks with lots of joints have low resistance to erosion. Hard rocks with a solid structure have a high resistance to erosion.
- Form where there are alternating bands of resistant and less resistant rock.
- Less resistant rocks eroded quickly snd forms a bay.
- Resistant rock is eroded more slowly and its left out forming a headland.
Headlands-Caves-Arches-Stack-Stump
- Usually made up go 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 cause a cave to form.
- Continued erosion deepens the cave until it breaks through the headland forming an arch.
- Erosion continues to wear way the rock supporting the arch, until it eventually collapses.
- Forms a stack, an isolated rock thats operate from the headland.
Transportation of material - Longshore Drift.
- Waves follow the direction of the prevailing winds.
- Usually hit the coast at an oblique angle.
- Swash carries material up the beach, the same direction as the waves.
- Backwash carries material down the beach at right angles, back towards the sea.
- Over time, material zig zags along the coast.
What is deposition?
- When material is being carried by the seawater and dropped on the coast. Occurs when water carrying sediment slows down so that it isn’t moving fast enough to carry so much sediment.