Call number:
ZSP-202-300
In:
Research report
Description / Table of Contents:
CONTENTS: Introduction. - Sampling. - Byrd Station. - Plateau Station. - Camp Century. - lnge Lehmann. - Grain-crystal relations. - Analytical techniques. - Thin sections. - Crystal size measurements. - Results and discussion. - Literature cited. - Appendix A: Crystal size as a function of depth and age in the Antarctic and Greenland ice sheets. - Abstract.
Description / Table of Contents:
The growth of ice crystals as a function of depth and time in polar firn and glacier ice has been investigated at a number of locations in Antarctica and Greenland. Thin sections of snow and ice were used to measure crystal size variations which showed, in all cases, that crystal size increases essentially linearly with the age of samples. Crystal growth rates are strongly temperature dependent. At Camp Century, Greenland, where the firn temperature is -24°C, crystals grow approximately 23 times faster than at Plateau Station, Antarctica, where the in situ temperature is -57°C. Extrapolation of the existing data indicates that crystal growth rates in polar firn and ice could be expected to vary by about two orders of magnitude over the temperature range -60°C to -15°C. Examination of the changes in the pore-crystal structure relationships to a dpeth of 100 m at Camp Century shows that these changes closely resemble those occuring in the full-scale isothermal sintering of powder compacts.
Type of Medium:
Series available for loan
Pages:
iii, 19 Seiten
,
Illustrationen
Series Statement:
Research report / Cold Regions Research and Engineering Laboratory, CRREL, US Army Material Command 300
URL:
http://www.worldcat.org/oclc/5974076
Language:
English
Branch Library:
AWI Library
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