14C-CH4 Measurements in Greenland Ice: Investigating Last Glacial Termination CH4 Sources

Citation:
Petrenko, VV, Smith AM, Brook EJ, Lowe D, Riedel K, Brailsford G, Hua Q, Schaefer H, Reeh N, Weiss RF, Etheridge D, Severinghaus JP.  2009.  14C-CH4 Measurements in Greenland Ice: Investigating Last Glacial Termination CH4 Sources. Science. 324:506-508.

Date Published:

Apr

Keywords:

age, atmospheric methane, c-14, carbon, climate, core, margin, radiocarbon, record, west greenland

Abstract:

The cause of a large increase of atmospheric methane concentration during the Younger Dryas-Preboreal abrupt climatic transition (similar to 11,600 years ago) has been the subject of much debate. The carbon-14 (C-14) content of methane ((CH4)-C-14) should distinguish between wetland and clathrate contributions to this increase. We present measurements of (CH4)-C-14 in glacial ice, targeting this transition, performed by using ice samples obtained from an ablation site in west Greenland. Measured (CH4)-C-14 values were higher than predicted under any scenario. Sample (CH4)-C-14 appears to be elevated by direct cosmogenic C-14 production in ice. C-14 of CO was measured to better understand this process and correct the sample (CH4)-C-14. Corrected results suggest that wetland sources were likely responsible for the majority of the Younger Dryas-Preboreal CH4 rise.

Notes:

n/a

Website

DOI:

10.1126/science.1168909