Published In

Journal of Glaciology

Document Type

Article

Publication Date

1-1-2001

Subjects

Kamb Ice Stream (Antarctica) -- Tributaries -- Behavior, Antarctica -- Kamb Ice, Stream Glaciers -- Antarctica

Abstract

The region where two active tributaries feed into the now stagnant Ice Stream C (ISC), West Antarctica, is thickening. In this region, we observe a correlation between faster ice flow (the tributaries) and elevated topography. We conclude that stagnation of ISC resulted in compression and thickening along the tributaries, eventually forming a "bulge" on the ice-sheet surface. Modern hydraulic potential gradients would divert basal meltwater from ISC to Ice Stream B (ISB). These gradients are primarily controlled by the bulge topography, and so likely formed subsequent to trunk stagnation. As such, we argue against "water piracy" as being the cause for ISC's stagnation. Kinematic-wave theory suggests that thickness perturbations propagate downstream over time, but that kinematic-wave speed decreases near the stagnant trunk. This and modest diffusion rates combine to trap most of the tributary-fed ice in the bulge region. Using interferometric synthetic aperture radar velocity measurements, we observe that half of the ice within ISC's southern tributary flows into ISB. That flow pattern and other observations of non-steady flow in the region likely result from stagnation-induced thickening along upper ISC combined with a longer period of thinning on upper ISB. If current trends in thickness change continue, more ice from upper ISC will be diverted to ISB.

Description

Originally appeared in Journal of Glaciology, published by the International Glaciological Society. Article can be found at http://www.igsoc.org/journal/

DOI

10.3189/172756501781832232

Persistent Identifier

http://archives.pdx.edu/ds/psu/8440

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