HR: 10:50h
AN: PP22B-03    [Abstracts]
TI: Gas Records From The West Greenland Ice Margin Covering The Last Glacial Termination: A Horizontal Ice Core
AU: * Petrenko, V V
EM: vpetrenko@ucsd.edu
AF: Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Drive, Mail Code 0244, La Jolla, CA 92093 United States
AU: Severinghaus, J P
EM: jseveringhaus@ucsd.edu
AF: Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Drive, Mail Code 0244, La Jolla, CA 92093 United States
AU: Brook, E J
EM: brooke@geo.oregonstate.edu
AF: Department of Geosciences, Oregon State University, 104 Wilkinson Hall, Corvallis, OR 97331 United States
AU: Reeh, N
EM: nr@oersted.dtu.dk
AF: Orsted-DTU, Technical University of Denmark, Orsteds plads, Building 348, Kgs. Lyngby, DK-2800 Denmark
AU: Schaefer, H
EM: schaefeh@geo.oregonstate.edu
AF: Department of Geosciences, Oregon State University, 104 Wilkinson Hall, Corvallis, OR 97331 United States
AB: Certain sites along ice sheet margins provide an easily accessible and almost unlimited supply of ancient ice at the surface. Measurements of gases in trapped air from ice outcropping at Pakitsoq, West Greenland, demonstrate that ancient air is mostly well preserved. No alterations in δ¹⁸O_atm and δ¹⁵N of N₂ are apparent, and alterations in methane are found in only a few ice sections. Using measurements of these gases, we have unambiguously identified a stratigraphic section containing ice from the Last Glacial Maximum, Bolling-Allerod, Younger Dryas and Preboreal intervals. Extensive sections of ice from the Holocene and most ages within the last glacial period are probably also present. Very accurate dating has been possible in the ice sections containing the Younger Dryas - Preboreal and the Oldest Dryas - Bolling abrupt climate transition signals. The ice at Pakitsoq is folded and non-uniformly thinned, with many cross-cutting bands of bubble-free ice and dust. The cross-cutting features are associated with anomalies in both the gas and the ice records. With careful sampling to avoid these, the ice at Pakitsoq is suitable for recovery of large-volume samples of the ancient atmosphere for analysis of trace constituents such as ¹⁴CH₄.
DE: 0473 Paleoclimatology and paleoceanography (3344, 4900)
DE: 0724 Ice cores (4932)
DE: 0792 Contaminants (0432)
DE: 0794 Instruments and techniques
DE: 1135 Correlative geochronology
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005