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Initial results from geophysical surveys and shallow coring of the Northeast Greenland Ice Stream (NEGIS)
Citation
Vallelonga, P and Christianson, K and Alley, RB and Anandakrishnan, JEM and Dahl-Jensen, D and Gkenis, V and Holme, C and Jacobel, RW and Karlsson, NB and Keisling, BA and Kipfstuhl, S and Kjaer, HA and Kristensen, MEL and Muto, A and Peters, LE and Popp, T and Riverman, KL and Svensson, AM and Tibuleac, C and Vinther, BM and Weng, Y and Winstrup, M, Initial results from geophysical surveys and shallow coring of the Northeast Greenland Ice Stream (NEGIS), The Cryosphere, 8, (4) pp. 1275-1287. ISSN 1994-0416 (2014) [Refereed Article]
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Copyright Statement
Copyright 2014 The Authors Licenced under the Creative Commons Attribution 3.0 License http://creativecommons.org/licenses/by/3.0/
DOI: doi:10.5194/tc-8-1275-2014
Abstract
The Northeast Greenland Ice Stream (NEGIS) is the sole interior Greenlandic
ice stream. Fast flow initiates near the summit dome, and the ice stream
terminates approximately 1000 km downstream in three large outlet glaciers
that calve into the Greenland Sea. To better understand this important
system, in the summer of 2012 we drilled a 67 m firn core and conducted
ground-based radio-echo sounding (RES) and active-source seismic surveys at
a site approximately 150 km downstream from the onset of streaming flow
(NEGIS firn core, 75°37.61' N, 35°56.49' W).
The site is representative of the upper part of the ice stream, while
also being in a crevasse-free area for safe surface operations.
Annual cycles were observed for insoluble dust, sodium and ammonium concentrations and for electrolytic conductivity, allowing a seasonally resolved chronology covering the past 400 yr. Annual layer thicknesses averaged 0.11 m ice equivalent (i.e.) for the period 1607–2011, although accumulation varied between 0.08 and 0.14 m i.e., likely due to flow-related changes in surface topography. Tracing of RES layers from the NGRIP (North Greenland Ice Core Project) ice core site shows that the ice at NEGIS preserves a climatic record of at least the past 51 kyr. We demonstrate that deep ice core drilling in this location can provide a reliable Holocene and late-glacial climate record, as well as helping to constrain the past dynamics and ice–lithosphere interactions of the Greenland Ice Sheet.
Annual cycles were observed for insoluble dust, sodium and ammonium concentrations and for electrolytic conductivity, allowing a seasonally resolved chronology covering the past 400 yr. Annual layer thicknesses averaged 0.11 m ice equivalent (i.e.) for the period 1607–2011, although accumulation varied between 0.08 and 0.14 m i.e., likely due to flow-related changes in surface topography. Tracing of RES layers from the NGRIP (North Greenland Ice Core Project) ice core site shows that the ice at NEGIS preserves a climatic record of at least the past 51 kyr. We demonstrate that deep ice core drilling in this location can provide a reliable Holocene and late-glacial climate record, as well as helping to constrain the past dynamics and ice–lithosphere interactions of the Greenland Ice Sheet.
Item Details
| Item Type: | Refereed Article |
|---|---|
| Keywords: | ice dynamics, shallow coring, geophysics |
| Research Division: | Earth Sciences |
| Research Group: | Physical geography and environmental geoscience |
| Research Field: | Glaciology |
| Objective Division: | Environmental Policy, Climate Change and Natural Hazards |
| Objective Group: | Understanding climate change |
| Objective Field: | Effects of climate change on Antarctic and sub-Antarctic environments (excl. social impacts) |
| UTAS Author: | Peters, LE (Dr Leo Peters) |
| ID Code: | 103752 |
| Year Published: | 2014 |
| Web of Science® Times Cited: | 44 |
| Deposited By: | IMAS Research and Education Centre |
| Deposited On: | 2015-10-27 |
| Last Modified: | 2017-10-30 |
| Downloads: | 586 View Download Statistics |
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