Please use this identifier to cite or link to this item: https://hdl.handle.net/11681/5920
Title: Deep core studies of the crystal structure and fabrics of Antarctic glacier ice
Authors: National Science Foundation (U.S.). Office of Antarctic Programs
Gow, A. J. (Anthony Jack)
Keywords: Antarctica
Byrd Station
Little America V
Glaciers
Glacier ice
Ice cores
Ice crystal growth
Ice crystal structure
Ice deformation
Ice fabrics
EPOLAR
EPOLAR
Publisher: Cold Regions Research and Engineering Laboratory (U.S.)
Engineer Research and Development Center (U.S.)
Series/Report no.: Research report (Cold Regions Research and Engineering Laboratory (U.S.)) ; 282.
Description: Research Report
Abstract: Radical differences in the crystal structure and fabrics of glacier ice cores at Byrd Station and Little America V, Antarctica, are attributed to gross differences in the thermal and deformational histories of the ice at these two locations. At Byrd Station the mean size of crystals increased more than sixfold between 65 m and the bottom of the drill hole at 309 m. Crystal size was also found to increase linearly with the age of the ice, thus simulating isothermal grain growth in metals. However, this growth was not accompanied by any dimensional orientation of crystals or entrapped bubbles, or by any significant increase in the degree of preferred orientation of crystallographic c-axes. These observations imply that negligible shearing is occurring in the top 300 m of the thick grounded ice sheet at Byrd Station. By contrast very considerable deformation is indicated for the floating 258-m-thick Ross Ice Shelf at Little America. This deformation is characterized by the widespread occurrence of "strained" crystals below 65 m, the existence of elongated oriented bubbles between 95 m and 130 m and the attainment of pronounced crystal orientation (multiple-maxima fabrics) by 100-m depth. Exaggerated growth of crystals below 150 m is attributed to increasing temperatures in the ice shelf. The crystal structure of these cores clearly demonstrates that glacial ice only is present in the Ross Ice Shelf at Little America V.
Rights: Approved for public release; distribution is unlimited.
URI: http://hdl.handle.net/11681/5920
Appears in Collections:Research Report

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