Glaciers Flashcards
Weathering
Process of wearing away or being worn away by long exposure to atmosphere, scree is evidence of weathering in glacial landscapes
Abrasion
As glacier moves down/uphill, rocks that have been frozen into base + sides of glacier scrape rock beneath (bedrock) + leave striations behind
Striations
Scratches in rock that glacier leaves behind when they move down/uphill
Plucking
Meltwater (formed by pressure of glacier itself) from glacier freezes around lumps of cracked + broken rock, when glacier moves down/uphill, rock is plucked from ground + into glacier, most effective when there are joints (cracks) in rocks that water can seep into
Freeze-thaw weathering
Occurs on rock surface above surface of ice + its margins, water from rain collects in cracks or holes in rock, overnight or seasonally it gets colder, so water freezes + expands as it traps air bubbles in it, expansion of crack puts pressure on it, which expands outwards or downwards, this process repeats overtime
Basil slip
In summer, meltwater lubricates glacier, enabling it to slide downhill
Rotational slip
More curved basil slip, happens in corries
Gravity
As ice accumulates (through snowfall/avalanche), glacier begins to flow under gravity
Glaciers’ movement when it’s too cold for basil slip
When temperatures are too cold for basil slip, glacier moves like plastic + speed is affected by gradient of slope, internal deformation happens here
Internal deformation
When individual ice crystals change shape
Moraine
Any material carried or moved by glacier, they can be transported on top of, in + below ice
Bulldozing
As glacier moves forward, it pushes loose debris at snout forwards
Deposition
Occurs when ice melts, which is mostly at snout of glacier, as glacier slowly retreats, it leaves behind till
Till/Boulder clay
Bed of broken rock fragments
Meltwater rivers
Ahead of glacier, meltwater rivers carry sediment away, attrition happens in these rivers, they deposit well sorted, rounded + sandy/gravelly material, forming outwash
Outwash
Well sorted, rounded + sandy/gravely material deposited by meltwater rivers
Firn
Really compact ice
Corrie
Sheltered hollow on upper slopes of glaciated valley, where valley glaciers begins
Formation of a corrie
Snow collects in sheltered hollow on side of mountain, nivation enlarge hollow, enabling more snow to collect, every winter, more snow collects in hollow, which compacts snow + squeezes out air, leaving ice, small corrie glacier has formed, back of wall gets steeper due freeze-thaw weathering + plucking, as glacier gets heavier, it moves downhill + out of hollow due to rotational slip, abrasion also takes place, corrie lip is formed due to less erosion at snout, after glacier has melted, lakes forms in hollow
Arête
Knife-edge ridge often found at back of corrie or separating 2 glaciated valleys, normally forms when 2 back to back corries causes land in between to become narrower
Pyramidal Peak
When 3 or more corries have formed on mountain, erosion may lead to formation of single peak rather than ridge
Glacial Trough/U-shaped valley
Formed by abrasion, most start out as v-shaped valley from rivers + are then eroded by glaciers
Truncated Spurs
They’re 2 interlocking spurs where glacier has cut straight through base of them + they’re steep-edged
Hanging Valleys
They’re small valleys where smaller glaciers, which were once in these valleys were unable to erode at same rate as main glacier
Ribbon Lakes
They’re long + narrow lakes formed due to severe erosion of glacial troughs, which happens as ice becomes thicker after tributary glacier has joined or where there was weaker band of rock
Corrie lake/tarn
Lake that forms after corrie glacier has melted
Ground Moraine
Material that is dragged underneath glacier + left behind, when ice melts, often forms uneven hilly ground
Lateral Moraine
Forms at edge of glacier, it’s most scree material that has fallen off valley sides due to freeze-thaw weathering, when ice melts, lateral (side) moraine forms low ridges on valley side
Medial Moraine
When tributary glacier joins main glacier, two lateral (side) moraines will merge to produce single line of sediment that runs down centre of main glacier, on melting, medial moraine forms ridges down centre of valley
Terminal Moraine
It’s huge amounts of material that pile up at snout of glacier to form high ridges, often tens of metres in height across valley, represents furthest extent of glacier’s advance
Drumlins
Egg-shaped hill that protrudes from ground, they’re made of mounds of deposited moraine that has been streamlined + shaped by moving ice, they have steep side (stoss end) + sloping side (lee slope), lee slope is more pointed + it’s end faces down valley, it indicates direction of movement of glacier, it’s streamlined + more gently sloping as till is dragged down slope by moving ice + it’s tapered end with downwards slope, some drumlins have rock core around them, where till can accumulate, stoss end faces direction ice is coming from, has steep end + is blunter end, ice flow goes from stoss end to lee slope
Erratics
They’re large boulders that sit on top of different types of landscapes, often have been transported huge distances by ice + are deposited far from their bedrock origin
Ice-Transported Boulders
Similar to erratics but are still found on their bedrock of origin + travel on top of ice
The Lake District: Location
Located in North-west of England in Cumbria + it’s along coast for some of it
The Lake District: Economic Opportunities
Tourism provides money for economy + jobs for local people, there are lots of adventure activities e.g abseiling, gorge scrambling or rock climbing, Lake District attracts lots of tourists e.g walkers, mountain bikers, fishers, abseilers + many more, who will probably spend their money there
Honeypot sites
Places with special interest or appeal that are very popular with visitors + normally tend to be overcrowded at peak times of year
The Lake District: Managment
Managing traffic congestion: several dual-carriageways have been built around Lake District to improve access, park-and-ride schemes have been expanded e.g Honister Rambler + transport hubs have been set up e.g Ambleside, which help to create interchange between parking, buses, ferries, walking + cycling, Managing footpath erosion: projects e.g Upland Path Landscape Restoration Project have been set up + have successfully repaired path, created steps, resurfaced paths with local stone + replanted native plants + other charities e.g ‘Fix the Fells’, who are supported by National Trust, use methods like stone-pitching, where large stones are dug into path, to create hard-wearing surfaces
The Lake District: Conflict
Jobs in tourism are mostly seasonal, poorly paid + unreliable, house prices are really high + 20% of property is either holiday rental or second homes, tourism creates traffic congestion on roads + tourists’ pollute environment from their vehicles + from boats that they hire/use, which damages ecosystems, tourists create litter, damage footpaths + farmland by trampling on crops + their dogs can disturb sheep + cattle
