Cold Environments Book 1 Flashcards
What is the difference between total accumulation total ablation for the whole of the glacial year called?
The glacial budget
Describe a polar glacier
The temperature of the ice remains well below freezing so it remains frozen to the bedrock so there is very little ice movement or erosion
How does gravity influence the flow of ice?
The downhill force of the ice encourages it to move. The steeper the gradient the greater the pull of gravity
In the summer what lubricates glaciers in Alpine areas?
Melt water helping them move down Valleys
How does the temperature of ice influence its flow?
If the ice is too cold it will simply freeze to the bedrock like in Greenland and Antarctica in more temperature environments such as Alaska temperatures are higher so there is more melt water
How does the mass of ice influence its flow?
The heavier the ice the more potential energy it has but it must overcome more friction ice masses don’t generally move until the thickness exceeds 60 m the greatest velocity of movement is at the firn line
What is the term for when ice changes directly from a solid to a vapour?
Sublimation
Is the Southern Ocean rich in animal life?
Yes despite being very cold
What do glacial or polar areas tend to be covered by?
Ice sheets and glaciers
What is the dividing line between the zone of accumulation and zone of ablation called?
The firn or equilibrium line
Describe the compressional flow
It occurs below the third line and it is slower and causes ice to bunch up in areas with less steep gradients. Any crevasses created by extension of flow will be closed
Describe basal flow/slippage
The movement of large blocks of ice usually in a series of short jerks. As the glacier moves there is friction, this is overcome by meltwater. The friction and pressure causes melting in the mouth water acts as a lubricant
How cold can winters be in Alpine areas and why?
Temperatures can drop to -10° or less due to high altitude
Where are tundra or periglacial areas found?
Dry high latitude areas such as northern Alaska and Canada, on the edge of polar environments
Why can a glacier be described as a system?
They have input and outputs
Where are the worlds largest glaciers found?
Polar regions
If ablation is greater than accumulation what happens?
Glacial retreat
Are cold environments only land based?
No they also include Maritime environment such as the Arctic and southern oceans
Where are the worlds most actively moving glaciers found?
Alpine areas
How does friction influence the flow of ice?
If the ice moves as one body the friction it exerts on the ground must be overcome
Describe regelation slip
When the glacier meets a small obstacle pressure builds up on the up stream side allowing it to melt and slip over the obstacle on the down glacial side due to a lower pressure the meltwater refreezes
What do Cold environments have a lot of and a little of?
They have a lot of snow and ice and little vegetation, they are sparsely populated
What are the two types of basal flow?
Regelation slip and creep
How does melt water influence ice flow?
It lubricates the ice allowing it to slip down hill