Middle to late Holocene chronology of the western margin of the Greenland Ice Sheet: A comparison with Holocene temperature and precipitation records

Middle to late Holocene chronology of the western margin of the Greenland Ice Sheet: A comparison with Holocene temperature and precipitation records

The response of the Greenland Ice Sheet to future climate change is relatively unconstrained. Determining the extents and rates of ice-margin fluctuations during the Holocene provides a longer-term perspective on ice-sheet changes and offers an analogue of how the ice-sheet may respond to future cha...

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Bibliographic Details
Published in:Arctic, antarctic, and alpine research Vol. 50; no. 1; p. 1
Main Authors: Levy, Laura B., Kelly, Meredith A., Applegate, Patrick A., Howley, Jennifer A., Virginia, Ross A.
Format: Journal Article
Language:English
Published: Boulder Taylor & Francis 01-01-2018
Taylor & Francis, Ltd
Taylor & Francis Ltd
Taylor & Francis Group
Subjects:
10be dating
Be dating
Bedrock
Beryllium 10
Boulders
Chronology
Climate change
Fjords
Fluctuations
Future climates
Greenland
Greenland ice sheet
Holocene
Ice
Ice sheets
Moraines
Paleoclimate
Precipitation
Sea level
Summer temperatures
Greenland
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Summary:The response of the Greenland Ice Sheet to future climate change is relatively unconstrained. Determining the extents and rates of ice-margin fluctuations during the Holocene provides a longer-term perspective on ice-sheet changes and offers an analogue of how the ice-sheet may respond to future changes. Here, we present sixteen new 10 Be ages of boulders on moraines, boulders perched on bedrock, and bedrock surfaces that mark the timing of ice-margin fluctuations during the Holocene in the Kangerlussuaq region of southern west Greenland. We show that the Keglen moraines date to 8.0 ± 0.3 ka (n = 6) and that the average ice-margin retreat rate slowed from about 49 to 13 m yr −1 after about 8.0 ka, likely in response to the ice margin retreating onto land at the head of the fjord Kangerlussuaq at this time. The average retreat rate further slowed to less than 1 m yr −1 between 6.8 ka and 4.2 cal kyr BP, a time when nearby paleoclimate records document warm summers and increased precipitation. Finally, we show that the historical advances of the ice margin occurred during the past 200 years, likely in response to cooler summer temperatures.
ISSN:1523-0430
1938-4246
DOI:10.1080/15230430.2017.1414477