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Cold glaciers
- PMP: Pressure melting
point is the temperature at
which ice is on the point of
melting. As pressure
increases this temperature
becomes lower.
- The way in which ice moves
depends on whether it is a warm
based (temperate) glacier such as
the Athabasca (Canada) or cold
based polar glacier - e.g. Merserve
Glacier, Antarctica
- E.g. Arctic/Antarctic
- High latitude locations
- Low relief
- Temperatures well below 0C
- Basal temperature below pressure melting point - frozen to bed
- As pressure
melting point not
reached no
meltwater
available.
- As pressure
melting point not
reached no
meltwater
available.
- Summer
temperatures may be
below freezing and
low precipitation
- Limited ablation and accumulation
- Movement is slow - Meserve Glacier Antarctica 3-4m per year
- Little erosion
- High latitude locations
- Main mechanisms for movement in cold based glacier is internal flow or internal deformation
- The ice deforms under its own weight because of gravity
- Intergranular flow - Crystals
reorientate in direction of
glacier movement and move
in relation to each other
- Laminar flow - movement of
individual layers within the glacier,
slide over each other resulting in
laminar flow
- Little friction so no melting and as the surface moves slightly faster crevasses
form. Movement n this way is very slow, tens of metres per year. The thicker the
ice , the faster internal deformation
- Intergranular flow - Crystals
reorientate in direction of
glacier movement and move
in relation to each other
- The ice deforms under its own weight because of gravity
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