Ventilation history of Nordic Seas overflows during the last (de)glacial period revealed by species-specific benthic foraminiferal 14C dates
Formation of deep water in the high‐latitude North Atlantic is important for the global meridional ocean circulation, and its variability in the past may have played an important role in regional and global climate change. Here we study ocean circulation associated with the last (de)glacial period,...
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American Geophysical Union
2017
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Online Access: | https://hdl.handle.net/10037/13126 https://doi.org/10.1002/2016PA003053 |
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ftunivtroemsoe:oai:munin.uit.no:10037/13126 2023-05-15T14:28:02+02:00 Ventilation history of Nordic Seas overflows during the last (de)glacial period revealed by species-specific benthic foraminiferal 14C dates Mohamed, Ezat M. Rasmussen, Tine L. Thornalley, David J.R. Olsen, Jesper Skinner, Luke C. Hönisch, Bärbel Groeneveld, Jeroen 2017-02-10 https://hdl.handle.net/10037/13126 https://doi.org/10.1002/2016PA003053 eng eng American Geophysical Union Ezat, M.M. (2015). North Atlantic–Norwegian Sea exchanges during the past 135,000 years: Evidence from foraminiferal ∆ 14 C, δ 11 B, δ 18 O, δ 13 C, Mg/Ca, and Cd/Ca. (Doctoral thesis). https://hdl.handle.net/10037/24869 . Paleoceanography info:eu-repo/grantAgreement/RCN/ SFF /223259/Norway/Centre for Arctic Gas Hydrate, Environment and Climate/CAGE/ Muhamed, M.E., Rasmussen, T.L., Thornalley, D.J.R., Olsen, J., Skinner, L.C., Hönisch, B. & Groeneveld, J. (2017). Ventilation history of Nordic Seas overflows during the last (de)glacial period revealed by species-specific benthic foraminiferal 14C dates. Paleoceanography, 32(2), 172-181. https://doi.org/10.1002/2016PA003053 FRIDAID 1449214 doi:10.1002/2016PA003053 0883-8305 1944-9186 https://hdl.handle.net/10037/13126 openAccess VDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Oseanografi: 452 VDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Marin geologi: 466 Nordic Seas Ocean ventilation Radiocarbon Last glacial Deglaciation Journal article Tidsskriftartikkel Peer reviewed 2017 ftunivtroemsoe https://doi.org/10.1002/2016PA003053 2022-04-27T22:58:30Z Formation of deep water in the high‐latitude North Atlantic is important for the global meridional ocean circulation, and its variability in the past may have played an important role in regional and global climate change. Here we study ocean circulation associated with the last (de)glacial period, using water‐column radiocarbon age reconstructions in the Faroe‐Shetland Channel, southeastern Norwegian Sea, and from the Iceland Basin, central North Atlantic. The presence of tephra layer Faroe Marine Ash Zone II, dated to ~26.7 ka, enables us to determine that the middepth (1179 m water depth) and shallow subsurface reservoir ages were ~1500 and 1100 14C years, respectively, older during the late glacial period compared to modern, suggesting substantial suppression of the overturning circulation in the Nordic Seas. During the late Last Glacial Maximum and the onset of deglaciation (~20–18 ka), Nordic Seas overflow was weak but active. During the early deglaciation (~17.5–14.5 ka), our data reveal large differences between 14C ventilation ages that are derived from dating different benthic foraminiferal species:Pyrgo and other miliolid species yield ventilation ages >6000 14C years, while all other species reveal ventilation ages <2000 14C years. These data either suggest subcentennial, regional, circulation changes or that miliolid‐based 14C ages are biased due to taphonomic or vital processes. Implications of each interpretation are discussed. Regardless of this “enigma,” the onset of the Bølling‐Allerød interstadial (14.5 ka) is clearly marked by an increase in middepth Nordic Seas ventilation and the renewal of a stronger overflow. Article in Journal/Newspaper Arctic Iceland Nordic Seas North Atlantic Norwegian Sea University of Tromsø: Munin Open Research Archive Norwegian Sea Paleoceanography 32 2 172 181 |
institution |
Open Polar |
collection |
University of Tromsø: Munin Open Research Archive |
op_collection_id |
ftunivtroemsoe |
language |
English |
topic |
VDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Oseanografi: 452 VDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Marin geologi: 466 Nordic Seas Ocean ventilation Radiocarbon Last glacial Deglaciation |
spellingShingle |
VDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Oseanografi: 452 VDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Marin geologi: 466 Nordic Seas Ocean ventilation Radiocarbon Last glacial Deglaciation Mohamed, Ezat M. Rasmussen, Tine L. Thornalley, David J.R. Olsen, Jesper Skinner, Luke C. Hönisch, Bärbel Groeneveld, Jeroen Ventilation history of Nordic Seas overflows during the last (de)glacial period revealed by species-specific benthic foraminiferal 14C dates |
topic_facet |
VDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Oseanografi: 452 VDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Marin geologi: 466 Nordic Seas Ocean ventilation Radiocarbon Last glacial Deglaciation |
description |
Formation of deep water in the high‐latitude North Atlantic is important for the global meridional ocean circulation, and its variability in the past may have played an important role in regional and global climate change. Here we study ocean circulation associated with the last (de)glacial period, using water‐column radiocarbon age reconstructions in the Faroe‐Shetland Channel, southeastern Norwegian Sea, and from the Iceland Basin, central North Atlantic. The presence of tephra layer Faroe Marine Ash Zone II, dated to ~26.7 ka, enables us to determine that the middepth (1179 m water depth) and shallow subsurface reservoir ages were ~1500 and 1100 14C years, respectively, older during the late glacial period compared to modern, suggesting substantial suppression of the overturning circulation in the Nordic Seas. During the late Last Glacial Maximum and the onset of deglaciation (~20–18 ka), Nordic Seas overflow was weak but active. During the early deglaciation (~17.5–14.5 ka), our data reveal large differences between 14C ventilation ages that are derived from dating different benthic foraminiferal species:Pyrgo and other miliolid species yield ventilation ages >6000 14C years, while all other species reveal ventilation ages <2000 14C years. These data either suggest subcentennial, regional, circulation changes or that miliolid‐based 14C ages are biased due to taphonomic or vital processes. Implications of each interpretation are discussed. Regardless of this “enigma,” the onset of the Bølling‐Allerød interstadial (14.5 ka) is clearly marked by an increase in middepth Nordic Seas ventilation and the renewal of a stronger overflow. |
format |
Article in Journal/Newspaper |
author |
Mohamed, Ezat M. Rasmussen, Tine L. Thornalley, David J.R. Olsen, Jesper Skinner, Luke C. Hönisch, Bärbel Groeneveld, Jeroen |
author_facet |
Mohamed, Ezat M. Rasmussen, Tine L. Thornalley, David J.R. Olsen, Jesper Skinner, Luke C. Hönisch, Bärbel Groeneveld, Jeroen |
author_sort |
Mohamed, Ezat M. |
title |
Ventilation history of Nordic Seas overflows during the last (de)glacial period revealed by species-specific benthic foraminiferal 14C dates |
title_short |
Ventilation history of Nordic Seas overflows during the last (de)glacial period revealed by species-specific benthic foraminiferal 14C dates |
title_full |
Ventilation history of Nordic Seas overflows during the last (de)glacial period revealed by species-specific benthic foraminiferal 14C dates |
title_fullStr |
Ventilation history of Nordic Seas overflows during the last (de)glacial period revealed by species-specific benthic foraminiferal 14C dates |
title_full_unstemmed |
Ventilation history of Nordic Seas overflows during the last (de)glacial period revealed by species-specific benthic foraminiferal 14C dates |
title_sort |
ventilation history of nordic seas overflows during the last (de)glacial period revealed by species-specific benthic foraminiferal 14c dates |
publisher |
American Geophysical Union |
publishDate |
2017 |
url |
https://hdl.handle.net/10037/13126 https://doi.org/10.1002/2016PA003053 |
geographic |
Norwegian Sea |
geographic_facet |
Norwegian Sea |
genre |
Arctic Iceland Nordic Seas North Atlantic Norwegian Sea |
genre_facet |
Arctic Iceland Nordic Seas North Atlantic Norwegian Sea |
op_relation |
Ezat, M.M. (2015). North Atlantic–Norwegian Sea exchanges during the past 135,000 years: Evidence from foraminiferal ∆ 14 C, δ 11 B, δ 18 O, δ 13 C, Mg/Ca, and Cd/Ca. (Doctoral thesis). https://hdl.handle.net/10037/24869 . Paleoceanography info:eu-repo/grantAgreement/RCN/ SFF /223259/Norway/Centre for Arctic Gas Hydrate, Environment and Climate/CAGE/ Muhamed, M.E., Rasmussen, T.L., Thornalley, D.J.R., Olsen, J., Skinner, L.C., Hönisch, B. & Groeneveld, J. (2017). Ventilation history of Nordic Seas overflows during the last (de)glacial period revealed by species-specific benthic foraminiferal 14C dates. Paleoceanography, 32(2), 172-181. https://doi.org/10.1002/2016PA003053 FRIDAID 1449214 doi:10.1002/2016PA003053 0883-8305 1944-9186 https://hdl.handle.net/10037/13126 |
op_rights |
openAccess |
op_doi |
https://doi.org/10.1002/2016PA003053 |
container_title |
Paleoceanography |
container_volume |
32 |
container_issue |
2 |
container_start_page |
172 |
op_container_end_page |
181 |
_version_ |
1766302155531091968 |