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SEM studies of the morphology and chemistry of polar ice

Barnes, Piers R.F.; Wolff, Eric W.; Mallard, David C.; Mader, Heidy M.. 2003 SEM studies of the morphology and chemistry of polar ice. Microscopy Research and Technique, 62. 62-69. 10.1002/jemt.10385

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Abstract/Summary

Determining the microphysical location of impurities in natural ice from the polar regions is necessary for understanding the physical properties of ice and for assuring the integrity of ice core records. SEM, using a cold stage and X-ray microanalytical techniques, has proved to be the most powerful method so far for undertaking such work. Methods are adapted from those used to study frozen hydrated biological material. Sublimation within the cryo-chamber is often needed in order to concentrate impurities onto a plane, but this can lead to artifacts that must be recognized. Over 100 samples from different depths and sites in Greenland and Antarctica have been examined. Typical physical features, including air bubbles, clathrate hydrates of air, and dust particles are identified. The dust is found preferentially at grain boundaries in some samples; by pinning the boundaries, it can slow grain growth. Of the soluble material, chloride seems to be found most frequently in the ice lattice. Other impurities are found at grain boundaries, and only when the bulk concentration exceeds a threshold, at triple junctions. These findings give new insights into processes determining the physical properties of ice samples and of ice sheets, and new impetus for theoretical studies of the energetics that lead to this distribution.

Item Type: Publication - Article
Digital Object Identifier (DOI): 10.1002/jemt.10385
Programmes: BAS Programmes > Antarctic Science in the Global Context (2000-2005) > Signals in Antarctica of Past Global Changes
ISSN: 1059-910X
Additional Keywords: Antarctic, Greenland, grain boundaries, triple junctions, soluble chemistry
NORA Subject Terms: Glaciology
Chemistry
Date made live: 17 Feb 2012 09:38
URI: http://nora.nerc.ac.uk/id/eprint/12587

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