Loading...
Depth-Varying Constitutive Properties Observed in an Isothermal Glacier
Marshall, H. P. Harper, J. T. Pfeffer, W. T. Humphrey, Neil
Marshall, H. P.
Harper, J. T.
Pfeffer, W. T.
Humphrey, Neil
Abstract
Description
Detailed three-dimensional in-situ measurements of deformation at depth are used to examine the rheology of a 6 x 106 m3 block of temperate glacier ice. Assuming that the viscosity of this ice is primarily dependent on stress, the relationship between inferred stress and measurements of strain-rate above similar to 115 m depth suggest a constitutive relationship with a stress exponent n similar to 1. Deformation below 115 m is described by a non-linear flow law with a power exponent of approximately 3-4. A sharp transition between the two flow regimes is likely caused by a change in the dominant mechanism from superplastic flow, basal slip, and/or diffusional flow near the surface to dislocation and intragranular deformation at depth.
Date
2002-12-14
Journal Title
Journal ISSN
Volume Title
Publisher
University of Wyoming. Libraries
Research Projects
Organizational Units
Journal Issue
Keywords
Geology