Distinctive Landscapes
- Created by: Riya.b123
- Created on: 08-03-19 16:59
UK Landscape
- Upland areas mostly found in North & West - generally formed of hard rock - resist erosion
- Many upland areas are glaciated areas - snowdonia - land often steep - cooler & wetter climates - thin soil allows vegetation to grow - sheep farming - quarrying - tourism
- Lowland areas mostly found in South & East - generally soft rock - landscape often flatter - warmer & drier climate - vegetation easily grows - mostly urban areas & industries
- Glaciated Landscapes - mostly upland in north-west
Weathering
- Mechanical - happens when temp alternatates above & below 0C - water gets into cracks of rocks - water freezes & expands which puts pressure on rock -when water thaws contracts - releases pressure - repeats until rock breaks
- Carbonation - rainwater has CO2 dissolved in it - weak carbonic acid with rock containing calcium carbonate
Mass Movement
- Causes coasts to retreat rapidly
- More likely to happen when material is full of water
- Acts as a lubricant
- Makes material heavier
- Undercutting of slope increases chance of mass movement
- 2 types of mass movement - Slides & Slumps
Erosion
- Hydraulic Action - waves crash against coast and rocks & compress air in rocks - pressure - repeated compression widens crack - rock breaks
- Abrasion - particles rub against rock in sea bed - removing small peices - wearing them away - rivers
- Attrition - particles (rocks) - smash against each other - break into smaller fragments
- Solution - Dissolved CO2 makes water slightly acidic
Transportation
- Traction - Large particles (boulders) pushed along river bed
- Suspension - Small particles (silt & clay) are carried along by water
- Saltation - Pebble sized particles bounce along river bed by force of water
- Solution - Soluble materials dissolved in water are carried along
Deposition
- Coastal Deposition - constructive waves carry material along the swash up to the coast - backwash takes very little material back down the coast - little erosion - amount deposited increases when lots of erosion - lots of material - lots of transportation
- River Deposition - river slows down - volume of water falls - amount of eroded material increases - water is shallower - river reaches it mouth
Headlands & Bays
- Form where there are alternating bands of resistant & less resistant rock along coast
- Less resistant rock erodes quickly - forms bays - gentle slope
- Resistant rock eroded slowly - forms headlands - steep sides - cracks
- Waves crash into headlands - hydraulic action & abrasion - causes cave to form - further erosion - cave breaks through headland - arch - continued erosion until collapse - stacks
Beaches
- Formed by deposition
- Found on coasts
- Formed by constructive waves - depositing materials such as sand & shingle
- Sand beaches - flat - wide - backwash can move sand particles - long & gentle slope
- Shingle beaches - steep - narrow - shingle particles are large - backwash can't move them up and down - create a steep slope
Longshore Drift
- Forms spits - waves follow direction of prevailing wind - hit coast at an angle - swash carries material - backwash carries material at right angles - overtime zigzags along coast
- Transports sand & shingle past bend - deposits in sea
- Strong winds can curve at end of spit
- Sheltered area behind spit - protected from waves - vegetation grows - overtime becomes salt marsh
Dorset Coast - Case Study
- Popular tourist destinaton in Southern England - Called Jurassic Coast - lots of fossils
- Variety of coastal landforms - sandy beaches
- The Foreland, Old Harry & His Wife - Foreland made of hard rock - headland collapsed to form stack (Old Harry) - Stump (Wife) - Weathering - Biological weathering
- Lulworth Cove - small bay - formed in Limestone - behind limstone is clay which eroded to form bay - limestone cliffs vulnerbale to mass movement
- Durdle Door - arch - hard limestone - cave developed into arch - mechanical -chemical - biological weathering
- Chesil Beach - type of spit - longshore drift - behind is a shallow lagoon
Dorset Coast Continued
- Warm, dry summers - mild, wet winters
- Salt weathering is common in summer - high evaporation
- Mild winter - freeze thaw weathering less common
- Exposed to prevailing wind - storms - destructive waves - increase in hydraulic action
- Low amounts of rainfall annually - very wet winters - vulnerable to carbonation weathering - increase in mass movement
- Coastal Management - Groynes - stops loss of beach material - makes beach narrower - more erosion - Sea walls - prevent erosion -removes sedient - Beach Replenishments - wider beaches - slow waves - costly
- Quarries vulnerable to chemical weathering - gravel removed from Chesil beach - Vegetation trampled
River Basin
- Seperated by a watershed
- Key features -
Tributary - source - mouth - course -
- channels & valleys which erode landscape - transport material to somewhere it is deposited
V - Shaped Valleys
- Formed by vertical Erosion in Upper Course - fast, flowing water allows boulders & rough particles to be transported along river bed
- Causes downward erosion of river channel by abrasion
- Valley sides are exposed to weathering - weathered materials fall into river channel causing further erosion
- River does not have energy to erode sideways so erodes vertically - deepens river valley
Waterfalls & Gorges
- Soft rock eroded by hydraulic action more than hard rock - creates an overhang
- Hard rock eventually collapses into plunge pool - more erosion - forms waterfall
- Collapsed hard rock erodes more by abrasion
- Overtime more undercutting causes more collapses - waterfall retreats - leaving a steep sided gorge
Meanders
- Formed by erosion & deposition
- Flow of water faster on outside of bend - river channel is deeper - less friction to slow water
- More erosion on outerside of bend - forming river cliffs
- Flow of water slower inside of bend - river channel is shallower - more friction
- Eroded material deposited inside of bend- forms slip of slopes
Oxbow Lakes
- Formed from meanders
- Erosion of meander causes outside of bends to get closer until small bit of land left between bends
- River breaks through land - during flood - river flows along shortest course
- Deposition cuts of meander - forms ox-bow lake
Floodplains
- When river floods onto floodplain - water slows - deposits eroded material - this builds up floodplain
- Meanders migrate across floodplains - wider - flatten valley floor
- Deposition happens on slipe of slopes of meanders - builds up floodplains
Levees
- Natural Embankments
- During flood eroded material deposited over floodplain
- Heaviest material deposited closest to river channel
- Overtime deposited material builds up - creates levees along edge of channel
Eden Basin - Case Study
- North - West England - Source is hills in Cumbria - mouth at Scottish Borders - faces prevailing wind - wettest part of UK
- Rural area - popular with tourists - variety of river landforms
- Waterfalls - gorge - V-shaped valleys - Floodplains - Meanders
- Mild winters - higher ground usually freezes - freeze thaw weathering upper course - mass movement - landslides common - material added to river
- Intense rainfall makes ground saturated - less stable - volume of water increases rapidly - increase in transportaton - more erosion
Coastal management - flood walls & embankments - prevents formation of meanders - Reservoirs - reduce buildup of floodplain - Planting Trees - reduces flooding - reduce erosion - Channel Management - artificial meanders- Deforestation has cleared many upland areas - increase of surface run off
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