Lawrence A. Wilen
R. B. Alley
J. J. Fitzpatrick
M. K. Spencer
A. J. Gow
C. L. Diprinzio
2005
<p><span>Preferred c-axis orientations are present in the firn at Siple Dome, West Antarctica, and recrystallization begins as shallow as 200 m depth in ice below –20°C, based on digital analysis of c-axis fabrics, grain-sizes and other characteristics of 52 vertical thin sections prepared in the field from the kilometer-long Siple Dome ice core. The shallowest section analyzed, from 22 m, shows clustering of </span><span class="italic">c</span><span> axes toward the vertical. By 200 m depth, girdle fabric and other features of recrystallized ice are evident in layers (or regions), separated by layers (regions) of typically finer-grained ice lacking evidence of recrystallization. Ice from about 700–780m depth, which was deposited during the last ice age, is especially fine-grained, with strongly vertical </span><span class="italic">c</span><span> axes, but deeper ice shows much larger crystals and strong evidence of recrystallization. Azimuthal asymmetry of some </span><span class="italic">c</span><span>-axis fabrics, trends in grain-size, and other indicators reveal additional information on processes and history of ice flow at Siple Dome.</span></p>
application/pdf
10.3189/172756505781829359
en
Oxford University Press
Fabric and texture at Siple Dome, Antarctica
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