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Glaciation - Coggle Diagram
Glaciation
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Cyrosphere : the cold areas were water is frozen [varies; climate (Britain in the Winter)] || Lake Baikai, Serbia
- Sea Ice and Ice Shelves
- ~7% of ocean surface
- Ice Shelf : snout of Glacier floating on the ocean, attached to the land (can go under the water into a bay) || Ross Ice Shelf, Antartica
- Breaks to form icebergs (Calving)
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- Glacial Environments
- Glaciers : pressured snow that moves due to gravity (sheer stress)
Global Scale
- Present :
- ~10% land area covered in glaciers
- 2 Ice sheets; Antarctic (86%) Greenland (11%), 3% Elsewhere (mountains)
- Past (18kyrs BP):
- ~30% land area covered in Glaciers
- 4 Icesheets; Antarctica, Greenland, Scandanavian, Laurentide
European Scale
- Present :
- Biggest Glaciers; Iceland || 12,200km², Norway || 3,800km², Alps || 3,600km²
- Past :
- Scandanavian ICecap covered most of Europe, Minus South-West England and South Europe
UK Scale
- Present : No Glacier
- Past :
- Most of UK (Scandanavian Icecap)
- Not the Southcoast
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Types of Glacier
- Definitions
- Neve/Firn : Last Years Snow
Warm Based Glaciers
(Grows in Size)
- Cirque Glaciers : armchair shaped hollow in the mountain side, constrained by the hollow || Cwm Idwal, N. wales
- Valley Glacier : flows down a mountain valley, the two mountain sides are steep in the glacial trough || Mer De Glace, Alps; Nant Ffrancon Valley, N. Wales (Devensian Period)
- Diedmont Glacier : Valley Glacier which gets to the flat lands and spreads over the low land areas (fan shaped), Unconstrained || Skaftarjökull, Iceland; Wye Glacier, Herefordshire (Devensian Period)
- Highland IceField : Effected by ground underneath, not as thcik as ice caps, No ice dome; influenced by the shape of the rock underneath || Glacier Du Geant Ice Fields, Mont Blonc
- Pressure changes the melting point of water; melts at -3º, and the ice is at -2º
- The ice is moving creating friction
- Volcanoes and Geothermic temperature changes can cause melting (Iceland)
- Erodes rock quicker; moves 1-2m/day
Cold Based Glaciers
(Cont. to grow in size)
- Ice Caps : submurge entire landscape (upto 50,000km²), centre of icecap is top of dome, ice flows down, ignores topography || Vatnajökull, Iceland
- Ice Sheet : Larger than 50,000km² || Greenland; Antarctic
- The ice temperature is significantly lower; the ice does not melt meaning it moves less
- 1-2/year
- Periglacial Landscapes
- Near glacier but does not have glaciers
- Too dry for glaciers
- Eg. Alaska, Siberia
- Permafrost ground
- Permafrost : ground remains at/or below 0º for >2yrs; 25% of the world
- Continuous Permafrost : highest latitude, ground is permanently frozen < several 100m deep
- Discontinuous Permafrost : Shallower, fragments of talik (unfrozen ground) – surface melts in summer
- Sporadic Permasfrost : Less than 50% of landscape, annual temp. is just below 0º
- Active Layer : Top layer that thaws
- Talik : unfrozen ground (Russian)
- Periglacial Processes
- Freeze-Thaw Weathering : water makes it way into the cracks in rocks, freezes and expands by 9% \ jointed rocks : rocks with many cracks
- Solifluction :