The Role of Lateral and Vertical Shear in Tributary Flow toward a West Antarctic Ice Stream

Narrow lateral shear margins are the most distinctive visual feature of the West Antarctic ice streams. Large shear stresses within these layers support the majority of the gravitational driving stress within a fast-flowing ice stream.The present contribution looks upstream, to the tributaries that...

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Bibliographic Details
Main Authors: Hulbe, Christina L., Wang, Weili, Joughin, Ian R., Siegert, Martin J.
Format: Text
Language:unknown
Published: PDXScholar 2003
Subjects:
Ice sheets > Antarctica
Glaciers > Antarctica
Ice sheets > Mathematical models
Ice shelves > Antarctica
Geology
Glaciology
Antarctic
Antarc*
Antarctica
Ice Shelves
Online Access:https://pdxscholar.library.pdx.edu/geology_fac/21
https://pdxscholar.library.pdx.edu/cgi/viewcontent.cgi?article=1020&context=geology_fac
Description
Summary:Narrow lateral shear margins are the most distinctive visual feature of the West Antarctic ice streams. Large shear stresses within these layers support the majority of the gravitational driving stress within a fast-flowing ice stream.The present contribution looks upstream, to the tributaries that feed ice-stream onsets, and considers the effects of both horizontal and vertical shear on their flow. Numerical and direct simulations of vertical and horizontal shear are used.Vertical shear, simulated using an anisotropic flow law, is of particular interest.We conclude that by isolating overlying ice from large-amplitude variations in bed elevation -vertical shear margins - play an important role in sustaining relatively rapid tributary flow.

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