EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

The age of surface-exposed ice along the northern margin of the Greenland Ice Sheet

Joseph MacGregor1, Mark Fahnestock2, William Colgan3, Nicolaj Larsen4, Kristian Kjeldsen3, and Jeffrey Welker5
Joseph MacGregor et al.
  • 1NASA Goddard Space Flight Center, Cryospheric Sciences Laboratory, Greenbelt, United States of America (
  • 2Geophysical Institute, University of Alaska Fairbanks, Fairbanks, Alaska, USA
  • 3Geological Survey of Denmark and Greenland, Copenhagen, Denmark
  • 4Section for GeoGenetics, Globe Institute, University of Copenhagen, Copenhagen, Denmark
  • 5Dept. of Biological Sciences, University of Alaska Anchorage, Anchorage, Alaska, USA

Each summer, surface melting of the margin of the Greenland Ice Sheet exposes a distinctive visible stratigraphy that is related to past variability in subaerial dust deposition across the accumulation zone and subsequent ice flow toward the margin. Here we map this surface stratigraphy along the northern margin of the ice sheet using mosaicked Sentinel-2 multispectral satellite imagery from the end of the 2019 melt season and finer-resolution WorldView-2/3 imagery for smaller regions of interest. We trace three distinct transitions in apparent dust concentration and the top of a darker basal layer. The three dust transitions have been identified previously as representing late-Pleistocene climatic transitions, allowing us to develop a coarse margin chronostratigraphy for northern Greenland. Substantial folding of late-Pleistocene stratigraphy is observed but uncommon. The oldest conformal surface-exposed ice in northern Greenland is likely located adjacent to Warming Land and may be up to ~55 thousand years old. Basal ice is commonly exposed hundreds of meters from the ice margin and may indicate a widespread frozen basal thermal state. We conclude that the ice margin across northern Greenland offers multiple compelling opportunities to recover paleoclimatically valuable ice relative to previously studied regions in southwestern Greenland.

How to cite: MacGregor, J., Fahnestock, M., Colgan, W., Larsen, N., Kjeldsen, K., and Welker, J.: The age of surface-exposed ice along the northern margin of the Greenland Ice Sheet, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-10963,, 2020

This abstract will not be presented.