WAIS Divide Ice Core Project - About: Site Selection
Site Selection
The WAIS Divide site location was chosen based on the following site requirements:
Relatively smooth bed topography and minimal horizontal ice flow.
Individually identifiable annual layers of at least 1cm thickness in
ice 40,000 years old.
Ice-accumulation rate sufficient to reduce the age difference between the
gases in the ice and the ice itself to less than 500 years.
Well-behaved stratigraphy to an age of at least 80,000 years.
High-resolution, grid-based airborne geophysical surveys of the Ross/Amundsen ice divide region were conducted during 1994-1996 and identified several sites with favorable surface topography, ice thickness, accumulation rate, and bedrock topography characteristics. On-ice site reconnaissance started in 1995/1996 with exploratory traverses into the area and the drilling of three shallow firn cores to confirm the preservation of climatic signals in the snow and ice. Ice flow modeling and temperature calculations were applied to the candidate sites to predict time scales and annual layer resolution. This was then followed by two seasons of ground-based geophysical surveys to further investigate the candidate sites.
The chosen WAIS Divide site is favored because:
bedrock topography is relatively smooth at km scales;
internal layers are flat and undisturbed;
location is ~24 km downsloap of the flow divide (but within 10 ice thicknesses of the divide) to insure that no divide migration has compromised the stratigraphy;
annual layers will be detectable (1 cm thick) to at least 40,000 years;
ice from deglacial period will not be brittle;
gas-age ice-age difference is ~200 years for the Holocene and ~300 to ~500
years for the last glacial period.
WAIS Divide Ice Core Project
This site is administered by the WAIS Divide Ice Core Project Science Coordination Office (Desert Research Institute and University of New Hampshire)
This material is based on work supported by the National Science Foundation under award OPP-0440817 to the Desert Research Institute, Nevada System of Higher Education.
Any opinions, findings, conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.
The WAIS Divide site location was chosen based on the following site requirements:
