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A Preliminary Model of Holocene Retreat and Thinning of Ice Stream E, West Antarctica (Abstract only)

Published online by Cambridge University Press:  20 January 2017

Craig S. Lingle  and
Charles R. Bentley
Craig S. Lingle
Affiliation:
Geophysical and Polar Research Center, University of Wisconsin, Madison, Wisconsin 53706, U.S.A.
Charles R. Bentley
Affiliation:
Geophysical and Polar Research Center, University of Wisconsin, Madison, Wisconsin 53706, U.S.A.
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Abstract

A preliminary numerical model of ice-stream grounding-line retreat and thinning as a function of eustatic sea-level rise has been developed. Grounding-line retreat is computed using the methods of Thomas and Bentley (1978). The change in thickness along the ice-stream profile is found by solving the equation of continuity in two dimensions during the time intervals corresponding to increments of grounding-line retreat. The model was applied to ice stream E, West Antarctica, assuming that the ice stream was initially grounded to the edge of the Ross Sea continental shelf.

Type
Research Article
Information
Annals of Glaciology , Volume 3 , 1982 , pp. 340
Copyright
Copyright © International Glaciological Society 1982

Grounding-line retreat was found to begin 12 ka BP after 40 m of eustatic sea-level rise, then to accelerate and proceed rapidly. The grounding line attained its present position by 9.44 ka BP, and retreat continued so that the grounding line was 200 km up-glacier from its present position by 8.75 ka BP, after 90 m of eustatic sea-level rise. About 700 m of thinning occurred on the upper flow line during the 2.56 ka required for the grounding line to retreat to its present position.

The model is preliminary, so it is not justifiable to conclude that the grounding line of ice stream E is unstable. Also, field evidence from the Ross Ice Shelf Geophysical and Glaciological Survey (Thomas and MacAyeal submitted for publication) suggests that the grounding line is in fact rather stable. Sea-floor bathymetry maps do not show asill capable of stabilising the grounding line at its present position, but stability might be caused by Roosevelt Island, which appears toinh bit discharge.

References

Thomas, R H, Bentley, C R 1978 A model for Holocene retreat of the West Antarctic ice sheet. Quaternary Research 10(2): 150–170 CrossRefGoogle Scholar