The causes of excess CO2 at the base of the Siple Dome ice core, Antarctica
Abstract
Ice cores are unique archives for the paleoatmosphere. However, this is not the case for ice from the base of the ice sheet, which usually shows high excess values of trace gases such as CO2 and CH4. This precludes the use of the basal ice as a reliable paleoatmospheric archive. However, the elevated values have the potential to provide information about physical and biological processes in the bottom of the ice sheet. The bottom 10 m (non-silty ice) of the Siple Dome ice core, Antarctica, shows enriched CO2 concentrations up to 800 ppm (mol CO2 / mol air), greater than known atmospheric values. Potential mechanisms for the excess CO2 include (1) ice melting/refreezing; (2) carbonate-acid reaction; (3) addition of volcanic CO2; and (4) oxidation of organic compounds biologically or abiologically. With the latest results from chemical and physical studies of the Siple Dome basal ice (CO2, CH4, O2/N2, Kr/N2, Xe/N2, 40Ar/36Ar, gas content, Ca2+ice, Na+ice) we will discuss the possible mechanisms for the in situ production of CO2 in the bottom ice sheet.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2005
- Bibcode:
- 2005AGUFMPP33C1597A
- Keywords:
-
- 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 0414 Biogeochemical cycles;
- processes;
- and modeling (0412;
- 0793;
- 1615;
- 4805;
- 4912);
- 0720 Glaciers;
- 0726 Ice sheets;
- 0776 Glaciology (1621;
- 1827;
- 1863)