低温科学 = Low Temperature Science;vol. 68, Supplement Issue

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The Stress Pattern within the Law Dome Summit to Cape Folger Ice Flow Line, Inferred from Measurements of Crystal Fabric

Donoghue, Shavawn;Jacka, Tim H.

Permalink : http://hdl.handle.net/2115/45439
KEYWORDS : ice crystal orientation fabrics;crystal size;ice sheet stress pattern;ice flow;Law Dome

Abstract

Crystal fabric and texture data are presented from ten ice cores that have previously been drilled along an approximate flow line extending from the summit of Law Dome ice cap to Cape Folger, East Antarctica. Our interest in these data is their interpretation in terms of stress patterns within the ice cap, and in particular the detection of the depths at which the stress changes from predominantly near-vertical compression to predominantly near-horizontal simple shear zones. This transition potentially marks an increase in flow rate, from a factor of ~3 in the compression zone to ~10 in the shear zone, compared to deformation of the initially isotropic ice that accumulates at the surface. Determining the depth of this potentially large change in flow rate between compression flow and shear flow provides valuable information for computer models of the ice sheet. In the Law Dome ice cap the compression-shear transition is found at approximately one-third of the total depth.

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