G2 Processes Flashcards
(23 cards)
What is the term for the balance between mass accumulation and ablation in glaciers?
Mass balance
What are the two main types of glacier motion?
Ice deformation and basal motion
What is the density range of fresh snow?
50-200 kg m-3
What is ‘firn’?
Wetted snow that has survived at least one melt season without being transformed to ice
What is the density range of firn?
400-830 kg m-3
What is the density range of glacier ice?
830-917 kg m-3
How does temperature affect the densification of snow to ice?
If T < 0°C, densification is slow; if T sometimes > 0°C, densification is faster due to melting and refreezing
What is ablation in the context of glaciers?
Loss of ice mass through melting, sublimation, calving, or wind erosion
What increases the stresses in glacier ice?
Thickness of the ice
What is basal motion?
Movement of glacier at its base; it slides over its bed
What conditions lead to basal motion in glaciers?
Presence of water at the glacier bed due to surface meltwater, pressure melting, or geothermal heat flux
What are the components of surface ablation?
Melting, evaporation, sublimation
What does a high albedo surface indicate?
It reflects a large proportion of short wave radiation back into space
What is the effect of a low albedo surface?
It absorbs a larger proportion of short wave radiation, making it more conducive to melt
What is iceberg calving?
A major component of ablation for tidewater glaciers
What are the three key processes of subglacial erosion?
- Crushing
- Abrasion
- Quarrying
What is the significance of glacial depositional processes?
Links landforms to types of glaciers and reconstructs past glacial environments
What drives the whole glacial system?
Inputs of potential energy and solar energy
Fill in the blank: The processes of glacial erosion result in classic glacial _______.
landscapes
What is the relationship between calving and air temperature?
There is a direct link between calving and air temperature, although it is complex
What does the annual mass balance of glaciers refer to?
Changes in mass balance through the year
Who were some early scientists that studied glacier flow?
- Forbes
- Agassiz
- Joseph Vallot
What is the defining characteristic of glaciers?
Their ability to move
