University of Oulu

Lane, T. P., Paasche, Ø., Kvisvik, B., Adamson, K. R., Rodés, Á., Patton, H., Gomez, N., Gheorghiu, D., Bakke, J., & Hubbard, A. (2020). Elevation Changes of the Fennoscandian Ice Sheet Interior During the Last Deglaciation. Geophysical Research Letters, 47(14). https://doi.org/10.1029/2020gl088796

Elevation changes of the Fennoscandian ice sheet interior during the last deglaciation

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Author: Lane, T. P.1; Paasche, Ø.2,3; Kvisvik, B.2,4;
Organizations: 1School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool, UK
2Bjerknes Centre for Climate Research, Bergen, Norway
3NORCE Climate, Bergen, Norway
4COWI, Bergen, Norway
5School of Science and the Environment, Manchester Metropolitan University, Manchester, UK
6NERC Cosmogenic Isotope Analysis Facility, Scottish Universities Environmental Research Centre, East Kilbride
7Centre for Arctic Gas Hydrate, Environment and Climate, The Arctic University of Norway, Tromsø, Norway
8Department of Earth and Planetary Sciences, McGill University, Montreal, Quebec, Canada
9Kvantum Institute, University of Oulu, Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 7.7 MB)
Persistent link: http://urn.fi/urn:nbn:fi-fe2020082864556
Language: English
Published: American Geophysical Union, 2020
Publish Date: 2020-08-28
Description:

Abstract

The dynamics and paleo‐glaciology of ice sheet interiors during the last deglaciation are poorly constrained, hindering ice sheet model reconstructions. We provide direct evidence of Fennoscandian Ice Sheet (FIS) interior behavior during deglaciation through surface exposure dating. Our results demonstrate early thinning of the FIS, prior to the Younger Dryas (YD, 12.8–11.7 ka). Interior thinning in central Norway was concurrent with retreat along the coastline, exposing ice‐free mountainous tracts, potentially as early as 20–15 ka. The FIS then formed moraines in these ice‐free tracts during the YD. This is contrary to current hypotheses advocating a landscape fully covered by cold, inactive ice during this period. Present empirical and model reconstructions fail to capture rapid interior downwastage, increasing uncertainties in ice sheet volume estimates and sea level contributions.

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Plain language summary

The decay of past ice sheets provides an analogue for the retreat of present‐day ice sheets, due to rapidly changing climate conditions experienced then and now. One limitation with ice reconstructions is, however, that they rarely contain dated evidence for how the ice sheet interiors behaved during their termination. In a new reconstruction of the geometry of the southern part of the Fennoscandian Ice Sheet (FIS), we overcome this limitation. We document that areas at the heart of the southern ice dome, previously thought to be consumed by thick ice, were in fact ice‐free 12,000 years ago suggesting that the FIS was considerably thinner than thought and that previous estimates of the ice sheet’s volume need to be recalculated.

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Series: Geophysical research letters
ISSN: 0094-8276
ISSN-E: 1944-8007
ISSN-L: 0094-8276
Volume: 47
Issue: 14
Article number: e2020GL088796
DOI: 10.1029/2020GL088796
OADOI: https://oadoi.org/10.1029/2020GL088796
Type of Publication: A1 Journal article – refereed
Field of Science: 1171 Geosciences
Subjects:
Funding: Fieldwork was supported by the Bjerknes Centre for Climate Research, LJMU's ECR Fellowship, and MMU's research fund. Sample processing was supported by a NERC CIAF Grant (9176‐0417). Thanks to Sheng Xu who completed the AMS measurements at SUERC. DEMs were provided by the Polar Geospatial Center under NSF‐OPP Awards 1043681, 1559691, and 1542736. H. P. and A. H. acknowledge support from the Research Council of Norway (RCN) through its Centres of Excellence funding scheme (Grant 223259) and the PetroMaks project “Glaciations in the Barents Sea area (GlaciBar)” (Grant 200672). The RCN funded project ACER (Grant 275181) is acknowledged by Ø. P. A. H. is grateful for an Academy of Finland ArcI visiting fellowship to the University of Oulu. T. L. and Ø. P. acknowledge the Advanced Climate Dynamics Courses (ACDC).
Dataset Reference: Supporting information:
  https://agupubs.onlinelibrary.wiley.com/action/downloadSupplement?doi=10.1029%2F2020GL088796&file=grl60830-sup-0001-2020GL088796-SI.docx
Copyright information: © 2020. The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
  https://creativecommons.org/licenses/by/4.0/