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...
Main Authors: | , , , |
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Format: | Text |
Language: | unknown |
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PDXScholar
2003
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Subjects: | |
Online Access: | https://pdxscholar.library.pdx.edu/geology_fac/21 https://pdxscholar.library.pdx.edu/cgi/viewcontent.cgi?article=1020&context=geology_fac |
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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