Mechanisms of ice movement - Internal deformation Flashcards
What is internal deformation (ice creep)?
Internal deformation is the slow creep of ice due to slippage between and within ice crystals as the ice crystals within the glacier orientate themselves in the direction of ice movement.
What moves during the process of internal deformation?
Movement is by the dislocation of individual ice crystals and not of the whole body of ice.
What happens when ice is subjected to pressure?
When ice is subjected to pressure, as at depth within a glacier, individual ice crystals deform and move in relation to each other.
Why is the volume of movement of ice crystals greatest at the base of the glacier?
The volume of movement is greatest at the base of the glacier where pressure is at its greatest.
How does the glacier begin to behave as a result of internal deformation?
As a glacier is made up of countless ice crystals, it will begin to behave as a plastic substance.
Is internal deformation more common in warm based or cold based glaciers?
Although internal deformation occurs in both warm and cold based glaciers, it is the main mechanism of movement in cold based glaciers, where basal sliding is virtually non-existent.
