HR: 1340h
AN: PP33C-1597 [Abstracts]
TI: The causes of excess CO2 at the base of the Siple Dome ice core, Antarctica
AU: * Ahn, J
EM: jinhoahn@gmail.com
AF: Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093
United States
AU: * Ahn, J
EM: jinhoahn@gmail.com
AF: Department of Geosciences, Oregon State University, Corvallis, OR 97331
United States
AU: Severinghaus, J
PP33C-1597
AF: Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093
United States
AU: Brook, E
PP33C-1597
AF: Department of Geosciences, Oregon State University, Corvallis, OR 97331
United States
AU: Headly, M
PP33C-1597
AF: Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093
United States
AU: Wahlen, M
PP33C-1597
AF: Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093
United States
AU: Suwa, M
PP33C-1597
AF: Department of Geosciences, Princeton University, Princeton, NJ 08544
United States
AU: Mayewski, P
PP33C-1597
AF: Climate Change Institute, University of Maine, Orono, ME 04469
United States
AU: White, J
PP33C-1597
AF: Institute of Arctic and Alpine Research (INSTAAR), University of Colorado, Bouldere, CO 80309
United States
AB:
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.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0414 Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912)
DE: 0720 Glaciers
DE: 0726 Ice sheets
DE: 0776 Glaciology (1621, 1827, 1863)
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005