2-1 Chapter 2

• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Antarctic; Greenland; Antarc*
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.425.2887; http://thesis.library.caltech.edu/4688/3/Chapter_2_Background.pdf

Atmosphere-, marine-, and soil-derived chemical species are incorporated into microcrystalline ices during their normal environmental cycles. It is generally assumed that species trapped in deep ice cores would be indefinitely preserved, thereby providing a reliable record of Earth’s paleoclimate. However, it has become apparent that ice contaminants are chemically transformed over geological timeframes, even under the low temperatures and apparent isolation prevalent at large depths. Of particular interest today are the apparent CO and CO2 excesses found in Greenland ice bubbles relative to contemporaneous Antarctic records prior to ca. 1500 AD. This recently observed phenomenon requires the in situ oxidation or decomposition of organic material below the firn line, i.e., after air bubbles are closed off in core sections strictly blocked from solar radiation. The detection of μg Kg-1 levels of dicarboxylic, oxocarboxylic, and dicarbonylic species in Greenland, but not in the cleaner Antarctic ice cores, lends material support to the hypothesis of ongoing chemical activity in deep ice cores. The