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| Titel |
Initial results from geophysical surveys and shallow coring of the Northeast Greenland Ice Stream (NEGIS) |
| VerfasserIn |
P. Vallelonga, K. Christianson, R. B. Alley, S. Anandakrishnan, J. E. M. Christian, D. Dahl-Jensen, V. Gkinis, C. Holme, R. W. Jacobel, N. B. Karlsson, B. A. Keisling, S. Kipfstuhl, H. A. Kjær, M. E. L. Kristensen, A. Muto, L. E. Peters, T. Popp, K. L. Riverman, A. M. Svensson, C. Tibuleac, B. M. Vinther, Y. Weng, M. Winstrup |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1994-0416
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| Digitales Dokument |
URL |
| Erschienen |
In: The Cryosphere ; 8, no. 4 ; Nr. 8, no. 4 (2014-07-22), S.1275-1287 |
| Datensatznummer |
250116247
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| Publikation (Nr.) |
 copernicus.org/tc-8-1275-2014.pdf |
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| Zusammenfassung |
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. |
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