Ice On Land Flashcards
Where are glaciers found?
High altitudes,
Low altitude and high latitudes.
What do glaciers do?
They erode, transport and deposit huge quantities of material.
What is the formation of a glacier called?
The formation of a glacier and the process by which they shape the landscape sound them is called glaciation.
Glacial?
Is a period of ice advance associated with falling temperatures.
Interglacial?
Is a period of ice retreat associated with rising temperatures (currently Holocene period).
What is internal deformation?
Is when the weight of the ice causes the deformation of ice crystals.
This takes place most readily where pressures are highest.
Glacier
A long standing mass of ice that moves very slowly downhill.
What is basal sliding?
When meltwater at the base of a glacier acts as a lubricant and the glacier slides over the land
When do glaciers move fastest?
- Increasing slope
- Increasing thickness of ice
- Increasing snowfall
- Increasing meltwater at the base a glacier
What is eccentricity?
A change in the Earth’s orbit
What is obliquity?
The tilt of the Earth’s axis
What is precession?
The Earth’s axis tilt
How are glaciers formed?
- As SNOW falls it becomes compacted as more snow falls on top of it
- Air is expelled and each individual ice snowflakes turn into GRANULAR ICE crystals
- The ice becomes denser turning into FIRN
- Then the firn turns into GLACIAL ICE
What are the outputs of a glacier?
- Ablation: usually occuring at the snout where temperatures are their highest (or on surface in the summer (melting!))
- Calving: where chunks of ice break away at the snout
- Evaporation: water liquid to water vapour
- Sublimation: water solid to water vapour
What are some inputs to the system?
Avalanches of snow and ice can also provide inputs to the system
What happens when the glacial budget is positive?
- Winter
- Accumulation: high
- Ablation: low
- Glacier: advances
What happens when the glacial budget is negative?
- Summer
- Accumulation: low
- Ablation: high
- Glacier: retreats
What is the impact of the short term temperature changes?
Seasonal change
- Summer: negative glacial budget as ablation EXCEEDS accumulation
- Winter: positive glacial budget as accumulation EXCEEDS ablation
What is the impact of the long term temperature changes?
Climate change
- Interglacial: negative glacial budget as ablation EXCEEDS accumulation
- Glacial: positive glacial budget as accumulation EXCEEDS ablation
What are long term changes that will effect the glacial budget?
- Global warming
- Glacial and interglacial periods
What is the Glacial Budget?
The glacial budget is the balance between accumulation and ablation in a glacier. It determines whether the glacier will advance or retreat
What is a Corrie glacier?
- It is the smallest type of glacier
- Rotational slip causes the ice to retreat from the back wall, creating a crevasse (which forms a corrie)
- E.G. Jasper National Park
What is a Valley glacier?
- A moving mass of ice confined within a valley
- Broad V shape
- Steeped wall (U-shaped Valley)
- E.G. Tongos National Forest: Alaska
What is an example of an Ice Cap and an Ice Sheet?
- Vamajokuu (Iceland)
- Senrial Rang (Antartica)