MacGregor JA, Fahnestock MA, Colgan WT, Larsen NK, Kjeldsen KK, Welker JM (2020). The age of surface-exposed ice along the northern margin of the Greenland Ice Sheet. Journal of Glaciology 66(258), 667–684. https://doi.org/10.1017/jog.2020.62
The age of surface-exposed ice along the northern margin of the Greenland Ice Sheet
|Author:||MacGregor, Joseph A.1; Fahnestock, Mark A.2; Colgan, William T.3;|
1Cryospheric Sciences Laboratory, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
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
5Department of Biological Sciences, University of Alaska Anchorage, Anchorage, Alaska, USA
6Department of Ecology and Genetics, University of Oulu, Oulu, Finland
|Online Access:||PDF Full Text (PDF, 2.7 MB)|
|Persistent link:|| http://urn.fi/urn:nbn:fi-fe2020091569491
Cambridge University Press,
|Publish Date:|| 2020-09-15
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 metres from the ice margin and may indicate a widespread frozen basal thermal state. We conclude that the ice margin across northern Greenland offers multiple opportunities to recover paleoclimatically distinct ice relative to previously studied regions in southwestern Greenland.
Journal of glaciology
|Pages:||667 - 684|
|Type of Publication:||
A1 Journal article – refereed
|Field of Science:||
We thank the Goddard Fellows Innovation Challenge for supporting JAM’s fieldwork and data analysis.
© The Author(s), 2020. Published by Cambridge University Press. This is an Open Access article, distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike licence (http://creativecommons.org/licenses/by-nc-sa/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the same Creative Commons licence is included and the original work is properly cited. The written permission of Cambridge University Press must be obtained for commercial re-use.