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| Titel |
The response of the southeast Greenland ice sheet to Holocene oceanographic variability |
| VerfasserIn |
Laurence Dyke, Camilla Andresen, Marit-Solveig Seidenkrantz, Tavi Murray |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250097366
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| Publikation (Nr.) |
 EGU/EGU2014-12938.pdf |
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| Zusammenfassung |
| Recent widespread changes around the marine-terminating margins of the Greenland Ice
Sheet (GrIS) have prompted concerns about the future stability of the ice sheet in a changing
climate. The southeast sector of the GrIS is highly dynamic and predominantly marine
terminating making it vulnerable to changes in oceanic circulation, yet the role of the oceans
in driving ice sheet evolution is not completely understood. The influx of warm, saline
subtropical waters have been demonstrated to ‘prime’ glaciers for retreat but the influence of
the oceans on the GrIS is poorly constrained, especially over timescales longer than ~150
years. Long-term records of ice sheet behaviour provide a baseline against which to assess the
magnitude of current changes and can provide insight into the mechanisms pacing glacial
change.
We present a suite of proxy data from a 175 cm long gravity core collected from the main
trough of Køge Bugt, southeast Greenland at a depth of 595 m. Køge Bugt is the drainage
portal for several large, fast-flowing GrIS outlet glaciers. The sediment core tracks changes in
both outlet glacier behaviour and oceanographic conditions. An age model is constructed
using 210Pb and 14C age determinations from marine bivalves and planktonic foraminifera;
the core provides a record of environmental change in Koge Bugt over the last
~6 ka; a period of significant climate variability. IRD counts, grain size and XRF
data are used to reconstruct glacial activity throughout the time period. Planktonic
foraminifera assemblage data provide a proxy for surface water conditions. We will also
attempt to reconstruct the flow strength and temperature variability of deep currents
from the mean sortable silt size and from benthic foraminifera assemblage data
respectively.
We present a record of surface and deep water change through the last 6 ka in southeast
Greenland. We examine how these influence the behaviour of the GrIS margin to assess the
mechanisms driving ice sheet change and to understand the magnitude of oceanic
forcing. |
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