Geography Y10 UK Landscapes and Coasts Flashcards
geology of upland areas
igneous and metamorphic rocks common - interlocking crystals means water and air can’t easily get in - more resistant
geology of lowland areas
sedimentary rocks - grains often have gaps between - easier to break, weather and erode - lower land
climate of upland areas
lower temperatures - higher altitude, higher precipitation - relief rainfall
climate of lowland areas
higher temperatures - lower altitude, lower precipitation - no relief rainfall
human uses of upland areas
mountaineering, skiing, hydroelectric power, pastoral farming, reservoirs, mining and quarrying
human uses of lowland areas
arable farming, big settlements, towns and cities, road networks, factories
what is a glacier
a large mass of ice that causes erosion
properties of glaciated landscapes
deep, wide, steep-sided U-shaped valleys
soil scraped away - thin soils
ridges form at end
knife-edged ridges (arêtes) and pyramidal peaks
tear-shaped mounds (drumlins) and mounds of angular material (moraines)
what are the geomorphic processes
weathering, erosion, transport, deposition, (mass movement)
types of erosion
attrition, abrasion, solution, hydraulic action
what is attrition
loose material crashing together
what is abrasion
rocks rubbing against bank/bed (river) or cliff (coast)
what is solution (erosion)
dissolving of rocks (often limestone)
what is hydraulic action
water entering cracks in the bank/bed or cliff with pressure breaking it
types of transport
traction, solution, suspension and saltation
what is traction
material rolling along the bed (too large to be picked up)
what is solution (transport)
dissolved into the water
what is suspension
held up in the water column
what is saltation
leapfrogging movement - one piece falls on the bed, which displaces others upwards
when does deposition occur
when energy is low
where does deposition occur in a river
inside of a meander and at the mouth
where does deposition occur on the coast
when there is low energy e.g. headland blocking strong winds entering bay
how does slumping occur
1) water infiltrates soil, increasing weight
2) weight increases and gravity pulls material down
3) wave cut notch created, increasing weakness
4) water acts as a lubricant, enabling material to slip
5) weight pulls material down in a rotational direction
types of lines of weakness
joints, faults, bedding planes
what is a joint
a crack within a bed
what is a fault
a crack across multiple beds
what is a bedding plane
a crack in between beds
how do smaller crystals affect weathering
smaller means more surface area and more gaps for water and air to get in
how do grains affect weathering
grains are porous - water and air can get in easier
what weathering is likely to occur in mountain environments
freeze thaw
what weathering is likely to occur in deserts
exfoliation, oxidation
what weathering is likely to occur in rainforests
decaying vegetation, tree woot wedging, chemical
what is erosion
the wearing away of the Earth’s surface and the removal of the material from its original location
what is weathering
the wearing away of the Earth’s surface in situ (not moved frorm the original location)
what is mass movement
the movement of material down slope of weathered material under the force of gravity - often fairly continues and varies speed slow~fast
what are the three types of weaathering
chemical, biological, physical
examples of chemical weathering
carbonation, oxidation
examples of biological weathering
growing roots and decaying vegetation
examples of physical weathering
exfoliation and freeze thaw
what is scree
a mass of small loose stones that form or cover a slope on a mountain
how does sliding occur
1) water infiltrates ground and builds up along a line of weakness - zone of lubrication
2) waves attack at the base causing erosion
3) lack of support - falls straight down into that area
4) material moves down cliff face in a straight line
what does discordant mean
different rock types meeting the coastline
what does concordant mean
same rock type along the coastline
what happens in constructive waves
strong swash and weak backwash means material is moved up the beach
what happens in destructive waves
no swash and strong bakwash means material is moved down the beach
under what conditions do constructive waves occur
gentle weather, lower frequency, lower energy
under what conditions do destructive waves occur
stromy weather, higher frequency, higher energy
how are bays formed
waves concentrate attacks on the weaker areas of rock, meaning it is eroded more and becomes a bay, the two more resistant areas of rock around it are the headlands
how are coves formed
there is a uniform wall of resistant rock where lines of weakness are exploited, alowing water to break through into weaker rock, which is eroded more than the resistant rock
what is it called when two coves join up
coalescence of coves
how does a cave go to a stump
1) line of weakness exploited by erosion - hydraulic action and abrasion, widened weakness - cave
2) most likely: fault line = plane with outcrops on both sides, which can erode through to make an arch
3) biological weathering on surface + arch edges eroding = roof of arch collapsing - stack
4) once erosion is large enough, the top of the stack collapses and becomes a stump
how does longshore drift work
material is moved up the beach at the angle of the prevailing wind (swash), but the backwash moves down the beach perpendicular to the coastline
how does a spit form
when there is a sharp corner in the headland, longshore drift continues straight in that direction
how do hooked ends form
when the wind direction periodically changes, so the longshore drift changes direction, before continuing in its previous direction
how can a spit stop extending
if water flow from inland is strong enough (such as a river estuary)
what environment is there inside a spit
low energy - muds and salts deposited - saltmarshes
what is the temperature like in Dorset
july ~ august - high temperatures (~20.5°C) - higher rates of chemical weathering - limestone higher rates of biological weathering - more plant growth
never cold enough (lowest ~ 9°C) for freeze thaw
what is precipitation like in Dorset
lowest (~50mm/month) - summer - still enough for biological growth, highest (~150mm/month) october ~ december - carbonation and solution + mass movement
what is wind direction like in Dorset
prevailing wind from south-west - longshore drift goes east
what is wind speed like in Dorset
winter - more storms - destructive waves, more transport, more mass movement
example of arch + facts
durdle door - formed as cove entrance ~10 000 yrs ago
- formed in portland limestone - resistant
- 61m high
example of cove + facts
lulworth cove - 125m entrance
- 400m widest point - wealden beds
- back of cove is chalk
example of bay + facts
swanage bay - between ballard point and peveril point
- 2.7km wide
- pier, concrete groyne (breakwater), groynes and sea wall
example of stack/stump + facts
Old Harry - ~20m high
- made of chalk
- arch and wave cut platform
Old Harry’s wife - became a stump in 1896
example of spit + facts
studland heath spit - ~3.7km long
- built up over ~ 400 yrs
- between handfast point and shell bay
what is rip-rap
large rocks of granite or ther hard igneous rocks placed at the bottom of cliffs which absorb energy by letting water drain through them
what is a groyne
a barrier made of rock or wood placed perpendicular to the coastline which traps sediment on one side which builds up the beach which helps absorb wave energy
what is a sea wall
a wall made of concrete or stone - can be sloping, curved, stepped and vertical - absorbs wave energy which prevents erosion
what are gabions
wire cages filled with stones placed at the bottom of cliffs to absorb wave energy
what are revetments
sloping barrier features on the coast made of wood or stone (rock armour), which absorb the energy of the waves, but still let water and sediment through
what are offshore reefs
large 245m long piles of granite rocks placed 250m from the sea wall parallel to the coastline, which cause waves to break early, thus reducing their strength
what is beach nourishment
transporting material from one area to another, to act as a barrier between the sea and the cliff
what is managed realignment
allowing the shoreline to move naturally, but directing it to certain areas to stop it from leading to erosion
advantage and disadvantage of rip-rap
cheaper than concrete constructions, traps flotsam and jetsam, leading to a smell and rat infestation
advantage and disadvantage of groynes
effective in a local context, requires ongoing maintenance
advantage and disadvantage of sea walls and revetments
effective property defence in high-risk locations, expensive to build and maintain + rapidly eroding
advantage and disadvantage of gabions
cheaper than other methods, prone to cage weathering (rusting) - doesn’t last very long
advantage and disadvantage of offshore reefs
work well alongside other management techniques, expensive to construct
advantage and disadvantage of beach nourishment
aesthetically pleasing - supports tourism, requires expensive annual replenishment
advantage and disadvantage of managed realignment
potential for estuary tidal reduction, politically sensitive (loss of land/property)
