glacier movement

Question 1

what is glacial movement

Answer 1

Glacial movement is the way in which a glacier stays in motion (internal deformation, basal slippage). This movement depends largely on the type of glacier (warm, cold, or polythermal-based)

Question 2

what is internal flow/internal deformation

Answer 2

Internal deformation occurs when the weight of the glacial ice causes its ice crystals to deform or ‘stretch out’. As a result, the glacier moves downslope very slowly (approximately 1-2cm a day). This process will continue, and adjacent crystals will overlap over one another as the glacier continues its advance.

Question 3

what is ice creep

Answer 3

ice crystals orient themselves in the direction of the glaciers movement
this allows ice crystals to slide past each other
as the surface ice moves faster crevasses may develop

Question 4

what is intergranular flow

Answer 4

between crystals grains of ice slip and flow past each other

Question 5

what is intragranular flow

Answer 5

inside crystals, crystals orientate themselves with the direction of flow

Question 6

what is enhanced basal creep

Answer 6

If there is an obstacle in the path of the glacier pressure will increase
as the stress builds up the ice behaves like plastic and flows around or over the obstacle
the lower the temperature, the greater the pressure needed to allow this process to take place and so it is less likely to occur in cold places

Question 7

what is extending and compressing flow

Answer 7

Where there is a reduction in gradient of the valley floor the ice will decelerate and become thicker
where the valley gradient is steep and the ice would accelerate and become thinner
erosion is greatest by the ice is biggest thickest