Holocene ice margin variations of the Greenland Ice Sheet and local glaciers around Sermilik Fjord, southeast Greenland

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Understanding the long-term difference in the response times of ice sheets, peripheral ice caps and glaciers may provide information about their respective sensitivities to climate change. However, there are only a few places where the history of local glaciers, ice caps (GICs) and the Greenland Ice Sheet (GrIS) have been recorded in the same area. In this study, we use proglacial threshold lake records from four sites around Sermilik Fjord, in southeast Greenland to determine the Holocene ice marginal variations. Combined with other published records from the area, we find that the GrIS margin receded to within its present extent in the Early Holocene ~9.6 cal ka BP, probably reaching its minimum extent by ~7.3 to 6.3 cal ka BP before readvancing to its maximum Late Holocene position between ~2.6 and 0.3 cal ka BP. The GICs began to retreat ~9.5 cal ka BP and completely melted away for an extended period between ~8 and 4 ka during the Middle Holocene. Regrowth of the GICs began during the early- and late Neoglacial and they reached their maximum extent between ~1.2 and 0.7 cal ka BP. In general, we find a coherent pattern of ice marginal variations between the GrIS and GICs, which coincides with the major Holocene climate changes. However, our results also demonstrate that there are differences in the synchronicity between individual records, which largely are dictated by the local topography that determines when ice marginal changes were recorded in proglacial lakes. Accordingly, this study illustrates both the advantages and limitations of the method and highlight the need for multiple proglacial lake records to constrain past glacier variations in a region.

OriginalsprogEngelsk
TidsskriftQuaternary International
Vol/bind607
Sider (fra-til)10-21
Antal sider12
ISSN1040-6182
DOI
StatusUdgivet - 2021

Bibliografisk note

Funding Information:
NKL was supported by Geocenter Danmark and Villum Young Investigator Programme. KHK was supported by grants from the Independent Research Fund Denmark, and the Danish National Research Foundation - Centre for GeoGenetics as well as GeoCenter Danmark. Peter Ilsøe and Jakob Holm are thanked for their help retrieving and analysing the cores from Smaragd Sø. We thank Anne-Ditte Nordmaj for help analysing the lake records from site 12. Glenn Milne is thanked for extracting HUY3 RSL curves. Two anonymous reviewers are thanked for their constructive comments that help improve the manuscript.

Publisher Copyright:
© 2021 The Author(s)

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