Glacial Bottom Processes
Most of the important processes controlling glacial motion occur in the ice-bed contact—even though it is only a few meters thick. Glaciers will move by sliding when the basal shear stress drops below the shear resulting from the glacier's weight.
- τD = ρgh sin α
- where τD is the driving stress, and α the ice surface slope in radians.
- τB is the basal shear stress, a function of bed temperature and softness.
- τF, the shear stress, is the lower of τB and τD. It controls the rate of plastic flow, as per the figure (inset, right).
For a given glacier, the two variables are τD, which varies with h, the depth of the glacier, and τB, the basal shear stress.
Read more about this topic: Ice Sheet Dynamics
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