Start date:
Early December 2009
End date:
Late January 2010
Taylor Gl
Principle Investigator:
Jeffrey Severinghaus
Scripps Institution of Oceanography
In order to develop a precise chronology of the exposed ice in the 20 km long Taylor Glacier ablation zone, field team members will sample ice for gas analyses. Prior research has shown that this ablation zone contains a unique, stratigraphically ordered sequence of ice at the surface, dating from approximately 8,000 to 70,000 years ago. This will allow researchers to obtain a horizontal ice core that will provide easily-accessed, large-volume samples of the past atmosphere and microparticles that are not currently available from other ice cores. The initial scientific objective is to test the hypothesis that methane clathrates were destabilized at times of abrupt warming during the last deglaciation, causing the observed abrupt increases in atmospheric methane concentrations known from prior ice core records. The hypothesis will be tested by measuring carbon-14 in large-volume samples (typically 100 liters) of ancient air obtained from the glacier, which is not possible from ice cores. This information will inform the future stability of methane clathrates in a human warmed world. In addition, the precise chronology for the horizontal ice core will permit a variety of future projects on other trace gases and particles. In this, the first of a three-year project, field team members will travel by helicopter to a field camp on Taylor Glacier. From there, they will travel by snowmobile to sample the entire 20 km length of the glacier outcrop. Using a custom-designed ice core drill, they will obtain several 10-inch diameter cores, down to a depth of 12 meters. They will use propane to melt the ice and extract the gasses. At the end of the field season they will transport their samples by air to the National Institute for Water and Atmospheric Research in Wellington, New Zealand, as well as to their home institutions.