CEEES/SC 10111-20111
Planet Earth
Glaciation Laboratory
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Chapter
Glaciers
= slow-moving, thick masses of ice that form when low temperatures and
sufficient snowfall allow winter snow and ice to survive the summer.
There are two main types of glaciers:
Alpine Glaciers. They begin at high
elevations and flow down preexisting stream valleys to lower
elevations, where they melt.
The valley is eroded – it becomes straighter, deeper, and wider than
the original stream valley and has a distinct “U-shape”,
rather than a “V-shape” profile.
Continental Glaciers: these are
thick, broad ice sheets that cover virtually the entire landscape.
Thickness may exceed 4,000 m and they are not confined by valley walls.
Material eroded by glaciers is transported by the moving ice and by
meltwater.
Deposition occurs when the ice melts or the running water slows.
Depositional features of Alpine Glaciers are distinctive when young,
but there are in areas of active erosion (formed in valleys or valley
mouths) they largely disappear in a geologically short period of time.
Continental glacier deposits may be several hundred meters thick and
impart a distinctive landscape that remains for a geologically long
period of time and may be converted to sedimentary rock.
Formation, Movement, and
Mass Balance
Erosional Landforms
Depositional Landforms