The deglaciation of coastal areas of southeast Greenland

Dyke, L. M., Hughes, A. L.C., Andresen, C. S., Murray, T., Hiemstra, J. F., Bjørk, A. A. and Rodés, Á. (2018) The deglaciation of coastal areas of southeast Greenland. Holocene, 28(9), pp. 1535-1544. (doi: 10.1177/0959683618777067)

Abstract

Large marine-terminating glaciers around the margins of the Greenland Ice Sheet have retreated, accelerated and thinned over the last two decades. Relatively little is known about the longer term behaviour of the Greenland Ice Sheet, yet this information is valuable for assessing the significance of modern changes. We address this by reporting 11 new beryllium-10 (10Be) exposure ages from previously uninvestigated coastal areas across southeast Greenland. The new ages are combined with existing data from the region to assess the timing of glacier retreat after the Last Glacial Maximum. The results show that deglaciation occurred first in the north of the region (~68°N) and progressed southwards. This north–south progression is attributed to the influence of the warm Irminger Current on the ice margin. Areas in the south of the region were isolated from the warm waters by the shallow bathymetry of the continental shelf. This demonstrates that oceanographic forcing paced the deglaciation of southeast Greenland through the Younger Dryas and early Holocene. In most areas of southeast Greenland bedrock ages are systematically older than their counterpart boulder samples; this offset is likely the result of inherited 10Be content in bedrock surfaces. This suggests that subglacial erosion during the last glacial cycle was insufficient to completely remove pre-existing 10Be content. Alternatively, this pattern may be the signature of a substantial retreat and advance cycle prior to final Holocene deglaciation.

• Item Type: Articles
• Additional Information: This manuscript is a contribution to the ‘Past and Future Dynamics of the Greenland Ice Sheet: What Is the Ocean Hiding?’ Project (Camilla Andresen; VILLUM Foundation, 10100). This project was conceived and samples were collected while Laurence Dyke was in receipt of a NERC CASE doctoral scholarship (NE/I528126/1). Samples were processed and analysed with support from a NERC CIAF grant (Laurence Dyke; 9123.0412). Fieldwork was supported by the Leverhulme Trust (Tavi Murray; GLIMPSE Project, F/00391/J) and National Geographic (Tavi Murray; 111741). Additional fieldwork was funded by the Danish Independent Research Council (FNU), the Danish Centre for Sea Research (DCH) and Geocenter Denmark (Camilla S Andresen; SEDIMICE Project).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Rodes, Dr Angel
• Authors: Dyke, L. M., Hughes, A. L.C., Andresen, C. S., Murray, T., Hiemstra, J. F., Bjørk, A. A., and Rodés, Á.
• College/School: College of Science and Engineering > Scottish Universities Environmental Research Centre
• Journal Name: Holocene
• Publisher: SAGE Publications
• ISSN: 0959-6836
• ISSN (Online): 1477-0911
• Published Online: 11 June 2018
• Copyright Holders: Copyright © 2018 The Authors
• First Published: First published in Holocene 28(9): 1535-1544
• Publisher Policy: Reproduced in accordance with the publisher copyright policy