Geoscience Reference
In-Depth Information
Extending flow
Compressive flow
Ogives
Shear
debris
cone
Deformation
(basal
surge)
Frozen to bed
- basal velocity zero
Sliding and
deformation
Block sliding
(Surging)
Internal
shear
Basal sliding
and slide slip
Internal
deformation
Surging
flow
Flow line
Shear plane
Figure 15.8
Principal styles of ice flow and glacier movement in plan and cross-section. Flow-parallel vertical sections are
shown below the glacier, with flow-parallel surface highlights and transverse plan sections above. Extending flow occurs in
icefalls and at the entrance to outlet glaciers. Compressive flow and ogives form at the base of outlet glaciers and icefalls.
Shearing occurs over stationary terminus ice.
Plate 15.4
Iceflow styles. Foliation (internal deformation) parallel to iceflow in the Rhône glacier (left) contrasts with extending
flow (due to basal sliding) and associated crevassing in the 0.5 km wide Breithorn glacier icefall (right) in Switzerland.
Photos: Ken Addison
