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Related Flashcards
Cards In This Set
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Bed Deformation
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Accounted for 90% of forward movement, high pore water pressure helps lubricate the sediments and makes them susceptible to conveyor-belt-like shearing movements. In essence it is like the front of a glacier is on roller blades being pushed from behind.
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Crevasse
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Shows location of glaciers surface where movement is faster than plastic flow, vertical cracks in the ice surface that can be a few cm wide or several meters wide, cracks can be fairly shallow or they can develop down to about 50 meters.
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Chevron Crevasse
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Formed by stress from valley walls. Introduced by drag on the valley walls by moving glacier. Ice moving at different speeds
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Splaying Crevasse
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Constriction down valley, Compressed flow, ice behind pushing too fast. 45 degrees from the valley sides are pointed up the valley. Over time the crevasses are pivoted and tend to straighten out
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Transverse Crevasse
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Ice accelerated away, ice in middle quite rapidly, cracks occur on side because they can't keep up to the speed of middle. 90 degrees from motion , initially they point up valley but overtime they point down valley
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Radial Crevasse
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Caused as extending flow surges into an opening in the landscape, forms at right angles then dissipates energy outwards, Common in piedmont glaciers as they encounter an open area an their energy is stretched out in all locations.
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Ogives
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Bands of alternating light and dark ice that occurs below an ice fall, represents different seasons
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Warm ice / Temperate glaciers
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-at or near pressure melting point-easy to melt-isolating snow pack-summer snow melt and ice melt-a lot of basil slipping-easy to move
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Cold over warm ice glaciers
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-Cold at surface, warmer near the bottom-Extreme thickness may produce enough pressure to bring a cold iced glacier up to the pressure melting point.
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Cold ice /cold based glaciers or Polar glaciers
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-no basil sliding component to their movement-Ice temps always remain below PMP-No surface melting
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Warm over cold ice
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-found near ablation zones-greater thickness can be cooled in winter than warmed in summer-base remains frozen year round
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Alpine Cirque Glaciers
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-Smallest (1-5km2)-High up-Headwaters-Areas that don't get much sun
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Alpine Valley Glaciers
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-Next largest-Larger than 5km2-Long valleys-Topography limited
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Piedmont Glaciers
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-Valley Glaciers-Discharge out into open plain-Radiates equally-Quite large
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Ice Caps
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-50,000km2-Completely cover landscape-No longer confirmed by the topography of an area-Radiates outwardly / Dome-like
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