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Were glacial iceberg surges in the North Atlantic triggered by climatic warming?

Moros, M; Kuijpers, A; Snowball, Ian LU ; Lassen, S; Backstrom, D; Gingele, F and McManus, J (2002) In Marine Geology 192(4). p.393-417
Abstract
High-resolution physical, mineralogical, sedimentological and micropalaeontological studies were carried out on North Atlantic cores from the Reykjanes Ridge at 59degreesN and from the region southwest of the Faeroe Islands. All core sites are situated along the pathway of Iceland-Scotland Overflow Water (ISOW) and the various parameters measured display similar features. Previously identified carbonate oscillations [Keigwin and Jones (1994) J. Geophys. Res., 99, 12397-12410] in the time span back to the Marine Isotope Stage 5-4 transition and Late Glacial lithic events [Bond and Lotti (1995) Science, 267, 1005-1010], such as the Heinrich ice-rafting events, are all represented in the core records. Long-term trends and higher-frequency... (More)
High-resolution physical, mineralogical, sedimentological and micropalaeontological studies were carried out on North Atlantic cores from the Reykjanes Ridge at 59degreesN and from the region southwest of the Faeroe Islands. All core sites are situated along the pathway of Iceland-Scotland Overflow Water (ISOW) and the various parameters measured display similar features. Previously identified carbonate oscillations [Keigwin and Jones (1994) J. Geophys. Res., 99, 12397-12410] in the time span back to the Marine Isotope Stage 5-4 transition and Late Glacial lithic events [Bond and Lotti (1995) Science, 267, 1005-1010], such as the Heinrich ice-rafting events, are all represented in the core records. Long-term trends and higher-frequency changes in ISOW intensity were reconstructed on the basis of various independent proxy records. The long-term trends in circulation match theoretical orbitally forced insolation changes. Our observed links between ice-rafted detritus (IRD) input, variations in sea surface temperature (SST) and circulation at greater depth point to the need to re-examine the origin of IRD events. We suggest that these events may have been triggered by enhanced, partly sub-surface, heat transport to the-north. Enhanced northward heat transport may have caused bottom melting of floating outlet glaciers and ice shelves, leading to increased iceberg discharge and ice sheet destabilization. This discharge. resulted in lower SST's and a lower temperature over Greenland. Thus, as shown by our records, this scenario implies a temporary de-coupling of surface processes and circulation at greater depth. A key feature is the occurrence of a-saw-tooth pattern in the marine data, which is similar to the Greenland ice core records. Moreover, the 'warming' theory of IRD events would explain the observed 'out-of-phase' relationship between the Greenland and Antarctic ice-core records and also the rapid establishment of higher temperatures over Greenland immediately after the cold phases (stadials) of the Dansgaard-Oeschger cycles. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
ice-rafting, Heinrich events, North Atlantic, magnetic susceptibility, detritus, palaeocurrents
in
Marine Geology
volume
192
issue
4
pages
393 - 417
publisher
Elsevier
external identifiers
  • wos:000182776200004
  • scopus:0347926488
ISSN
0025-3227
DOI
10.1016/S0025-3227(02)00592-3
language
English
LU publication?
yes
id
67fae26e-8c60-424c-9425-d10e9aed8ecc (old id 311969)
date added to LUP
2007-11-02 12:22:02
date last changed
2017-07-02 04:29:36
@article{67fae26e-8c60-424c-9425-d10e9aed8ecc,
  abstract     = {High-resolution physical, mineralogical, sedimentological and micropalaeontological studies were carried out on North Atlantic cores from the Reykjanes Ridge at 59degreesN and from the region southwest of the Faeroe Islands. All core sites are situated along the pathway of Iceland-Scotland Overflow Water (ISOW) and the various parameters measured display similar features. Previously identified carbonate oscillations [Keigwin and Jones (1994) J. Geophys. Res., 99, 12397-12410] in the time span back to the Marine Isotope Stage 5-4 transition and Late Glacial lithic events [Bond and Lotti (1995) Science, 267, 1005-1010], such as the Heinrich ice-rafting events, are all represented in the core records. Long-term trends and higher-frequency changes in ISOW intensity were reconstructed on the basis of various independent proxy records. The long-term trends in circulation match theoretical orbitally forced insolation changes. Our observed links between ice-rafted detritus (IRD) input, variations in sea surface temperature (SST) and circulation at greater depth point to the need to re-examine the origin of IRD events. We suggest that these events may have been triggered by enhanced, partly sub-surface, heat transport to the-north. Enhanced northward heat transport may have caused bottom melting of floating outlet glaciers and ice shelves, leading to increased iceberg discharge and ice sheet destabilization. This discharge. resulted in lower SST's and a lower temperature over Greenland. Thus, as shown by our records, this scenario implies a temporary de-coupling of surface processes and circulation at greater depth. A key feature is the occurrence of a-saw-tooth pattern in the marine data, which is similar to the Greenland ice core records. Moreover, the 'warming' theory of IRD events would explain the observed 'out-of-phase' relationship between the Greenland and Antarctic ice-core records and also the rapid establishment of higher temperatures over Greenland immediately after the cold phases (stadials) of the Dansgaard-Oeschger cycles.},
  author       = {Moros, M and Kuijpers, A and Snowball, Ian and Lassen, S and Backstrom, D and Gingele, F and McManus, J},
  issn         = {0025-3227},
  keyword      = {ice-rafting,Heinrich events,North Atlantic,magnetic susceptibility,detritus,palaeocurrents},
  language     = {eng},
  number       = {4},
  pages        = {393--417},
  publisher    = {Elsevier},
  series       = {Marine Geology},
  title        = {Were glacial iceberg surges in the North Atlantic triggered by climatic warming?},
  url          = {http://dx.doi.org/10.1016/S0025-3227(02)00592-3},
  volume       = {192},
  year         = {2002},
}