Holocene history of the Greenland Ice-Sheet margin in Northern Nunatarssuag, Northwest Greenland
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Lauren Farnsworth(1); Meredith Kelly(1); Gordon Bromley(2); Yarrow Axford(3); Erich Osterberg(1); Jennifer Howley(1); Margaret Jackson(1); Susan R. Zimmerman(4)
(1)Dartmoth College; (2)National University of Ireland. Galway; (3)Northwestern University; and (4)Lawrence Livermore National Laboratory
Greenland Ice Sheet
Holocene, Glacial geomorphology
The Greenland Ice Sheet has experienced an increased net loss of mass since the mid-1990s due to increased surface melting and iceberg calving. This loss is contributing approximately 0.7 mm per year to global sea-level rise and highlights the importance of modelling the sensitivity of the ice sheet to future warming.
One way to understand the sensitivity of the Greenland Ice Sheet to climate conditions is to compare past ice sheet changes with independently reconstructed palaeoclimate conditions. This study presents a record of Greenland Ice Sheet fluctuations in NW Greenland, focusing on the margins of the ice sheet and ice-free areas in the Nunatarssuaq region (~ 20 km north-east of Thule Air Base). Using geomorphic mapping, cosmogenic 10Be surface-exposure dating of glacial deposits, and radiocarbon (14C) dating of subfossil plants recently exposed by ice recession, comparisons are made between past ice sheet extents and local and regional climate records. This allows researchers to predict how the Greenland Ice Sheet is likely to respond to current and future climate conditions.
The results of this study suggest that the Greenland Ice Sheet was minimally erosive when it covered northern Nunatarssuaq and deposited the Nuna III drift. Geomorphic evidence and ages derived from 10Be and 14C document a significant advance of Nuna and Tunge Rampen at ~ 3.2 to 2.1 thousand years ago, which was likely influenced by cooler summer temperatures during the Neoglacial. The latest Holocene advance of most Greenland Ice Sheet margins, as well as the advance at ~3.2 to 2.1 ka of Nuna and Tunge Rampen, are consistent with insolation-driven cooling through the Holocene.
The study was funded by the U.S. National Science Foundation.
Holocene; Greenland Ice Sheet; Cosmogenic nuclide surface exposure dating; Radiocarbon dating; Glacial geomorphology