Unit 3: Distinctive Landscapes

a landscape is made up of

all the visible features of an area of land

natural landscapes have

more physical features (and less human features)

built landscapes have

more human features (and less physical features)

where are upland areas found in the UK?

upland areas are found in the north and west of the UK

characteristics of upland areas

generally made of harder rocks giving thin soils

many are glaciated landscapes and very steep

climate is cooler and wetter giving lots of rough vegetation

land uses of upland areas

forestry

sheep farming

quarrying

tourism

where are lowland areas found in the UK?

lowland areas are found in the south and east of the UK

characteristics of lowland areas

generally made of softer rocks giving fertile soils

flatter and gently rolling hills

climate is warmer and drier giving vegetation, grassy meadows and deciduous forests

land uses of lowland areas

quarrying

tourism

dairy and arable farming

urban areas and industries

how do U shaped valleys form?

U shaped valleys formed during the last glacial period

ice had covered the north and west of the UK

ice was able to erode the landscape carving out valleys

what happened when the glaciers melted?

lots of material was deposited as the ice melted

the glacial meltwater and deposits formed landscapes in the south and east of the UK

what is mechanical weathering, with an example?

mechanical weathering is the breakdown of rock without changing its chemical composition

freeze-thaw weathering

how does freeze-thaw weathering occur?

temperatures fall below 0°C at night

water in the cracks of rocks freezes

the water expands when it freezes

when the ice melts the crack widens and eventually breaks

what is chemical weathering, with an example?

chemical weathering is the breakdown of rock by changing its chemical composition

carbonation weathering

how does carbonation weathering occur?

rainwater has carbon dioxide dissolved in it

the carbonic acid reacts with calcium carbonate in limestone

the rock is broken down

what is biological weathering?

biological weathering is the breakdown of rock by living things

give two examples of biological weathering

plant roots grow into cracks on rock surfaces

this pushes the rock apart

animals burrow into the rocks

what is mass movement?

the shifting of rocks down a slope/cliff

which leads to rapid coastal retreat

what are the two types of mass movement?

slide, when the material falls in a straight line

slump, when the material rotates down

how does mass movement occur?

the rain saturates the rock, making it heavier

erosion from waves undercut a slope

eventually, the rock falls due to a lack of support

what are the four types of erosion?

hydraulic action

abrasion

attrition

solution

what is hydraulic action?

hydraulic action is when waves crash against rocks

these forces air into cracks

the pressure in the rock increases and it breaks

what is abrasion?

abrasion is when eroded particles in water rub against the rock in the sea bed, cliffs, or river channel

this removes small pieces and wears them away

what is attrition?

attrition is when eroded particles smash into each other

they break down into smaller fragments

their edges get rounded off as they rub together

what is solution (erosion)?

solution is when the water dissolves some rocks

dissolved carbon dioxide can make the water acidic

so the acid reacts with some rocks

what are the four types of transportation?

traction

saltation

suspension

solution

what is traction?

traction is when large particles are pushed along the river bed/sea floor

what is saltation?

saltation is when pebble-sized rocks are bounced along the floor

what is suspension?

suspension is when small particles like sand or silt float and are carried along the water

what is solution (transportation)?

solution is when soluble materials dissolve into the water and are carried along the water

how does deposition occur?

the water carrying sediment loses velocity

the material carried is then dropped

how does coastal deposition occur?

constructive waves bring up lots of material

they also take back little material

this is because they have a large swash and small backwash

how does river deposition occur?

at shallow waters there is more eroded material

this reaches the mouth where it is deposited

how does longshore drift occur?

waves follow the prevailing wind direction

they hit the coast at an oblique angle

the swash carries material in the same direction

the backwash brings the wave down at a 90° angle

over time the material zig-zags along the coast

how do headlands form?

headlands form when there is a band of hard rock

the hard rock is eroded slowly, leaving a headland

this sticks out with steep sides

how do bays form?

bays form when there is a band of soft rock

the soft rock is eroded quickly, leaving a bay

this has a gentle slope

how do caves form?

caves form when waves crash into headlands

this creates cracks, which are enlarged

hydraulic action and abrasion occur to widen the cracks

this eventually forms a cave

how do arches form?

arches form when erosion deepens the cave all the way through

how do stacks and stumps form?

stacks form when erosion and weathering wear away the rock supporting the arch

the stack is further eroded to make a stump

how do beaches form?

beaches are formed by constructive waves that deposit sand and shingle

what are the characteristics of sandy beaches?

sandy beaches are gently sloped and long

the sand is small enough to be moved down by backwash

what are the characteristics of shingle beaches

shingle beaches are steep and narrow

the shingle is far too big to be moved down by backwash

how do spits form?

spits form at sharp bends on the coastline by longshore drift

strong winds and waves can curve the end of the spit

the sheltered area is protected from waves

how do salt marshes and mud flats form?

salt marshes and mud flats form when material accumulates in the sheltered area behind a spit

longshore drift continues

what is a river basin?

a river basin is the area of land surrounding a river

any rain that falls here makes its way into the river

what is a watershed?

a watershed is a ridge of high land that separates river basins

what is a tributary?

a tributary is a smaller river that joins a main river

what is the source of a river?

the source is where a river starts

it is usually in an upland area

what is the mouth of a river?

the mouth is where a river flows into a sea / lake

it is usually in a lowland area

what is the course of a river?

the course is the path of a river

there is the upper course, middle course, and lower course

what landforms are found in the upper course of a river?

V shaped valleys

waterfalls

gorges

plunge pools

how do V shaped valleys form?

V shaped valleys form from fast flowing water, heavy rain, and turbulence

boulders are transported down leading to abrasion

the valley sides are exposed to weathering

more material fall into the water, leading to more abrasion

there is not enough energy for lateral erosion

so there is mostly vertical erosion

how do waterfalls form?

waterfalls form when a river flows over an area of hard rock onto an area of soft rock

the softer rock is eroded by hydraulic action and abrasion

this creates a step in the river

the softer rock is eroded more until a steep drop is formed

this creates a waterfall

how do plunge pools form?

plunge pools form when the hard rock at the waterfall is eventually undercut by erosion

it becomes unsupported and collapses

the collapsed rocks are swirled around at the foot of the waterfall, eroding the softer rock by abrasion

this creates a deep plunge pool

how do gorges form?

gorges form when the waterfall retreats

more undercutting causes more collapsing

this leaves a steep sided gorge behind

what landforms are found in the middle course of a river?

meanders

oxbow lakes

how do meanders form?

meanders are formed by erosion and deposition

water naturally flows in a corkscrew fashion

the water is faster on the outside of the bend

and is slower on the inside of the bend

how do river cliffs form?

river cliffs form on the outside of a meander

the current is faster because the channel is deeper

there is less friction to slow the water down

more erosion takes place on the outside of the bend

how do slip off slopes form?

slip off slopes form on the inside of the meander

the current is slower because the channel is shallower

the eroded material is deposited on the inside of the bend

how do oxbow lakes form?

oxbow lakes form when erosion causes the outside bend to get smaller until there is a small bit of land between the meanders called a neck

during a flood, the river breaks through the neck

the river then flows along the shortest course

deposition eventually cuts off the meander

this forms an oxbow lake

what landforms are found in the lower course of a river?

floodplains

leeves

how do floodplains form?

floodplains form when the wide valley floor on either side of the river gets flooded

the water slows down and deposits eroded material

this builds up the floodplain

how do meanders affect floodplains?

meanders migrate across the floodplain, making it wider

meanders migrate downstream, flattening the valley floor

the deposition on the slip-off slopes builds up the floodplain

what are leeves?

leeves are natural embankments (raised bits) along the edges of a river channel

how do levees form?

levees form during a flood, where eroded material is deposited over the floodplain

the heaviest material is deposited closest to the river channel

this is because it gets dropped first when the river slows down

the deposited material builds up creating levees