GLACIAL FLOW PROCESSES & PATTERNS

A. Introduction

How do glaciers move?

What are the spatial and temporal patterns to flow?

B. Flow Processes

1. Basal Sliding

a. glacier temperature

b. character of bedrock-ice interface

2. Plastic Deformation or Plastic Flow

a. stress and strain

b. shear stress: t = r gh sinq

where t = shear stress

r = density of ice (0.9 g/cm³)

g = acceleration of gravity (980 cm/s/s)

h= thickness of glacier

q = slope

3. Internal Shearing

4. Regelation

C. Flow Patterns

1. Ice Thickness: maximum velocity at surface & decreases with depth

2. Position   

a. center versus sides

a. maximum velocity & discharge at the equilibrium line

3. Compressive and Extending Flow  

4. Temporal variations

D. Summary