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AS Geography
Cold environment - Content…read more

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Key words
· Glacial environment ­ covered by ice and glaciers e.g.
· Periglacial/Tundra environment ­ not permanently
covered by ice but has permafrost e.g. Alaska
· Alpine environment ­ Mountainous e.g. Europe Alps
· Supraglacial ­ On top of glacier
· Englacial ­ Rocks fall into crevasse in the glacier and
transported within/Other processes within
· Subglacial ­ Rocks fall into crevasse in the glacier and
ends up at the bottom. Also material gathered from
beneath via plucking. Also other processes underneath
the glacier…read more

Slide 3

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Ice formation
· Cold climate ­ more precipitation (snow)
· Shorter summers ­ less time for snowmelt
· Snow cover all year round
· Climate gets worse snow survives
Snow to Ice
· Snow falls containing a lot of air
· Layers of snow build up annually ­ lower levels
become harder due to the weight ­ called firn
· Any melt water sneaks into layers and refreezes ­
makes firn even harder
· Weight squeezes out any air turning firn into ice
· Air makes ice white ­ without it turns blue…read more

Slide 4

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Mass Balance
· Accumulation > Ablation = positive mass
balance = glacial advance
· Ablation > Accumulation = negative mass
balance = glacial retreat
· Accumulation = Ablation = equilibrium =
· Ablation = process of snow or ice melting
· Accumulation = net gain in an ice mass (snowfall)
· Melting can occur from heat, pressure and friction…read more

Slide 5

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Climate influences leading to glaciers
· Changes in earths orbit
· Variations in sunspot activity
· Volcanic dust
· Trapping of Co2 in oceans
· Variations in ocean currents
Types of Glaciers
Warm Cold
Scientific name Temperate Polar
Basal temperature (bottom
>0°C <0°C
of glacier meets rock)
Melting Yes No
Relief (steepness) Steeper Gentle
Basal flow, Extended flow,
Types of flow (how it Internal Deformation/ice
compressive flow, creep
moves) ripping apart
and surge (BECCS)…read more

Slide 6

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How do warm glaciers move - BECCS
· Basal Flow ­ as glacier moves over the bedrock friction creates heat ­
melt water created acts as lubricant
· Extending flow ­ Valley gets steeper ­ ice speeds up, gets thinner and
splits creating crevasses and seracs
· Compressing flow ­ Valley is flat, ice slows down and becomes thicker
­ more ice more erosion
· Creep ­ When ice meets an obstacle increasing pressure makes the ice
act like plastic and flow around it
· Surges ­ Water build up under the glacier/mass of snow on
accumulation zone ­ leads to massive distance movement per day (up
to 250-300m)
How cold glaciers move
Internal deformation ­ temperature is so cold ice is frozen to bedrock
· Ice crystals move to face same direction as the glacier ­ gravity
· As this happens they slide past each other making the glacier move
very slowly…read more

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