Persistent Nordic deep-water overflow to the glacial North Atlantic
North Atlantic climate is very sensitive to overturning in the Greenland-Iceland-Norwegian (GIN) Seas, overflow of deep water into the North Atlantic via the Greenland-Iceland-Scotland Ridge, and compensating northward flow of warm surface water. Physical models suggest that, in the absence of such...
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2011
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Online Access: | https://oceanrep.geomar.de/id/eprint/21249/ https://doi.org/10.1130/G31677.1 |
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ftoceanrep:oai:oceanrep.geomar.de:21249 2023-05-15T16:28:28+02:00 Persistent Nordic deep-water overflow to the glacial North Atlantic Crocket, K. C. Vance, D. Gutjahr, Marcus Foster, G. L. Richards, D. A. 2011 https://oceanrep.geomar.de/id/eprint/21249/ https://doi.org/10.1130/G31677.1 unknown GSA, Geological Society of America Crocket, K. C., Vance, D., Gutjahr, M. , Foster, G. L. and Richards, D. A. (2011) Persistent Nordic deep-water overflow to the glacial North Atlantic. Geology, 39 (6). pp. 515-518. DOI 10.1130/G31677.1 <https://doi.org/10.1130/G31677.1>. doi:10.1130/G31677.1 Article PeerReviewed 2011 ftoceanrep https://doi.org/10.1130/G31677.1 2023-04-07T15:09:13Z North Atlantic climate is very sensitive to overturning in the Greenland-Iceland-Norwegian (GIN) Seas, overflow of deep water into the North Atlantic via the Greenland-Iceland-Scotland Ridge, and compensating northward flow of warm surface water. Physical models suggest that, in the absence of such overturning, oceanic heat transport to the Northern Hemisphere is reduced by as much as 50%, open North Atlantic sea-surface temperatures are as much as 6 °C lower, and the winter sea-ice limit migrates as far south as 45°N. Although simulations of the equilibrium climate state for the Last Glacial Maximum (LGM) suggest the absence of GIN Seas overflow, tests of these model results have been hampered by ambiguity in sedimentary proxies. Here we present a bottom-water neodymium (Nd) isotope record from the Rockall Trough to investigate changes in the sources of circulating waters over the past 43 k.y. Today and throughout most of the Holocene, water from the GIN Seas, along with water from the North Atlantic Current (NAC) entrained during overflow, sets the bottom-water Nd isotope composition of the Rockall Trough to ∼–10. Our results suggest the persistence of this scenario back into the LGM and beyond to mid-Marine Isotope Stage 3. Periodic radiogenic excursions punctuate the record at times of meltwater events, implying either continued GIN Seas overflow without NAC entrainment, or millennial-scale interruptions in the overflow and shoaling of Southern Source Water. We conclude that overflow was at least intermittently present during the LGM, if not continuous, and that the GIN Seas have remained a source of deep water to the North Atlantic during the last glacial cycle. Article in Journal/Newspaper Greenland Iceland north atlantic current North Atlantic Sea ice OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Greenland Rockall Trough ENVELOPE(-15.036,-15.036,53.825,53.825) Geology 39 6 515 518 |
institution |
Open Polar |
collection |
OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
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ftoceanrep |
language |
unknown |
description |
North Atlantic climate is very sensitive to overturning in the Greenland-Iceland-Norwegian (GIN) Seas, overflow of deep water into the North Atlantic via the Greenland-Iceland-Scotland Ridge, and compensating northward flow of warm surface water. Physical models suggest that, in the absence of such overturning, oceanic heat transport to the Northern Hemisphere is reduced by as much as 50%, open North Atlantic sea-surface temperatures are as much as 6 °C lower, and the winter sea-ice limit migrates as far south as 45°N. Although simulations of the equilibrium climate state for the Last Glacial Maximum (LGM) suggest the absence of GIN Seas overflow, tests of these model results have been hampered by ambiguity in sedimentary proxies. Here we present a bottom-water neodymium (Nd) isotope record from the Rockall Trough to investigate changes in the sources of circulating waters over the past 43 k.y. Today and throughout most of the Holocene, water from the GIN Seas, along with water from the North Atlantic Current (NAC) entrained during overflow, sets the bottom-water Nd isotope composition of the Rockall Trough to ∼–10. Our results suggest the persistence of this scenario back into the LGM and beyond to mid-Marine Isotope Stage 3. Periodic radiogenic excursions punctuate the record at times of meltwater events, implying either continued GIN Seas overflow without NAC entrainment, or millennial-scale interruptions in the overflow and shoaling of Southern Source Water. We conclude that overflow was at least intermittently present during the LGM, if not continuous, and that the GIN Seas have remained a source of deep water to the North Atlantic during the last glacial cycle. |
format |
Article in Journal/Newspaper |
author |
Crocket, K. C. Vance, D. Gutjahr, Marcus Foster, G. L. Richards, D. A. |
spellingShingle |
Crocket, K. C. Vance, D. Gutjahr, Marcus Foster, G. L. Richards, D. A. Persistent Nordic deep-water overflow to the glacial North Atlantic |
author_facet |
Crocket, K. C. Vance, D. Gutjahr, Marcus Foster, G. L. Richards, D. A. |
author_sort |
Crocket, K. C. |
title |
Persistent Nordic deep-water overflow to the glacial North Atlantic |
title_short |
Persistent Nordic deep-water overflow to the glacial North Atlantic |
title_full |
Persistent Nordic deep-water overflow to the glacial North Atlantic |
title_fullStr |
Persistent Nordic deep-water overflow to the glacial North Atlantic |
title_full_unstemmed |
Persistent Nordic deep-water overflow to the glacial North Atlantic |
title_sort |
persistent nordic deep-water overflow to the glacial north atlantic |
publisher |
GSA, Geological Society of America |
publishDate |
2011 |
url |
https://oceanrep.geomar.de/id/eprint/21249/ https://doi.org/10.1130/G31677.1 |
long_lat |
ENVELOPE(-15.036,-15.036,53.825,53.825) |
geographic |
Greenland Rockall Trough |
geographic_facet |
Greenland Rockall Trough |
genre |
Greenland Iceland north atlantic current North Atlantic Sea ice |
genre_facet |
Greenland Iceland north atlantic current North Atlantic Sea ice |
op_relation |
Crocket, K. C., Vance, D., Gutjahr, M. , Foster, G. L. and Richards, D. A. (2011) Persistent Nordic deep-water overflow to the glacial North Atlantic. Geology, 39 (6). pp. 515-518. DOI 10.1130/G31677.1 <https://doi.org/10.1130/G31677.1>. doi:10.1130/G31677.1 |
op_doi |
https://doi.org/10.1130/G31677.1 |
container_title |
Geology |
container_volume |
39 |
container_issue |
6 |
container_start_page |
515 |
op_container_end_page |
518 |
_version_ |
1766018122778673152 |