Document Type

Article

Publication Title

Journal of Geophysical Research-Solid Earth and Planets

Rights and Access Note

This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. In addition, no permission is required from the rights-holder(s) for educational uses. For other uses, you need to obtain permission from the rights-holder(s).

Publication Date

1991

First Page

11649

Last Page

11655

Volume Number

96

Abstract/ Summary

Ice thickness, computed within the fjord region of Byrd Glacier on the assumptions that Byrd Glacier is in mass-balance equilibrium and that ice velocity is entirely due to basal sliding, are on average 400 m less than measured ice thicknesses along a radio-echo profile. We consider four explanations for these differences: (1) active glacier ice is separated from a zone of stagnant ice near the base of the glacier by a shear zone at depth; (2) basal melting rates are some 8 m/yr; (3) internal shear occurs with no basal sliding in much of the region above the grounding zone; or (4) internal creep and basal sliding contribute to the flow velocity in varying proportions above the grounding zone. Large gradients of surface strain rate seem to invalidate the first explanation. Computed values of basal shear stress (140 to 200 kPa) provide insufficient frictional heat to melt the ice demanded by the second explanation. Both the third and fourth explanations were examined by making simplifying assumptions that prevented a truly quantitative evaluation of their merit. Nevertheless, there is no escaping the qualitative conclusion that internal shear contributes strongly to surface velocities measured on Byrd Glacier, as is postulated in both these explanations.

Citation/Publisher Attribution

Scofield, JP, Fastook, JL, and Hughes, TJ, 1991, Evidence for a Frozen Bed, Byrd Glacier, Antarctica: Journal of Geophysical Research-Solid Earth and Planets, v. 96, p. 11649-11655. To view the published open abstract, go to http://dx.doi.org and enter the DOI.

Publisher Statement

© Copyright 1991 American Geophysical Union

DOI

10.1029/91JB00839

Version

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In Copyright - Educational Use Permitted.