Ventilation history of Nordic Seas overflows during the last (de)glacial period revealed by species-specific benthic foraminiferal 14 C 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,...
Published in: | Paleoceanography |
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Language: | English |
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2017
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Online Access: | https://pure.au.dk/portal/en/publications/7685acac-32bf-46b1-bd83-6c85b32c7f39 https://doi.org/10.1002/2016PA003053 http://www.scopus.com/inward/record.url?scp=85013382096&partnerID=8YFLogxK |
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ftuniaarhuspubl:oai:pure.atira.dk:publications/7685acac-32bf-46b1-bd83-6c85b32c7f39 2024-02-11T10:01:35+01:00 Ventilation history of Nordic Seas overflows during the last (de)glacial period revealed by species-specific benthic foraminiferal 14 C dates Ezat, Mohamed M. Rasmussen, Tine L. Thornalley, David J. R. Olsen, Jesper Skinner, Luke C. Honisch, Barbel Groeneveld, Jeroen 2017-02 https://pure.au.dk/portal/en/publications/7685acac-32bf-46b1-bd83-6c85b32c7f39 https://doi.org/10.1002/2016PA003053 http://www.scopus.com/inward/record.url?scp=85013382096&partnerID=8YFLogxK eng eng https://pure.au.dk/portal/en/publications/7685acac-32bf-46b1-bd83-6c85b32c7f39 info:eu-repo/semantics/openAccess Ezat , M M , Rasmussen , T L , Thornalley , D J R , Olsen , J , Skinner , L C , Honisch , B & Groeneveld , J 2017 , ' Ventilation history of Nordic Seas overflows during the last (de)glacial period revealed by species-specific benthic foraminiferal 14 C dates ' , Paleoceanography , vol. 32 , no. 2 , pp. 172-181 . https://doi.org/10.1002/2016PA003053 ARCTIC-OCEAN CARBON-DIOXIDE CIRCULATION DEEP DEGLACIATION GLACIAL PERIOD ICE-CORE NORTH-ATLANTIC SEDIMENTS WATERS Nordic Seas last glacial radiocarbon ocean ventilation article 2017 ftuniaarhuspubl https://doi.org/10.1002/2016PA003053 2024-01-17T23:59:42Z 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 14 C 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 14 C ventilation ages that are derived from dating different benthic foraminiferal species: Pyrgo and other miliolid species yield ventilation ages >6000 14 C years, while all other species reveal ventilation ages <2000 14 C years. These data either suggest subcentennial, regional, circulation changes or that miliolid-based 14 C 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 Arctic Ocean Climate change Foraminifera* ice core Iceland Nordic Seas North Atlantic Norwegian Sea Aarhus University: Research Arctic Arctic Ocean Norwegian Sea Paleoceanography 32 2 172 181 |
institution |
Open Polar |
collection |
Aarhus University: Research |
op_collection_id |
ftuniaarhuspubl |
language |
English |
topic |
ARCTIC-OCEAN CARBON-DIOXIDE CIRCULATION DEEP DEGLACIATION GLACIAL PERIOD ICE-CORE NORTH-ATLANTIC SEDIMENTS WATERS Nordic Seas last glacial radiocarbon ocean ventilation |
spellingShingle |
ARCTIC-OCEAN CARBON-DIOXIDE CIRCULATION DEEP DEGLACIATION GLACIAL PERIOD ICE-CORE NORTH-ATLANTIC SEDIMENTS WATERS Nordic Seas last glacial radiocarbon ocean ventilation Ezat, Mohamed M. Rasmussen, Tine L. Thornalley, David J. R. Olsen, Jesper Skinner, Luke C. Honisch, Barbel Groeneveld, Jeroen Ventilation history of Nordic Seas overflows during the last (de)glacial period revealed by species-specific benthic foraminiferal 14 C dates |
topic_facet |
ARCTIC-OCEAN CARBON-DIOXIDE CIRCULATION DEEP DEGLACIATION GLACIAL PERIOD ICE-CORE NORTH-ATLANTIC SEDIMENTS WATERS Nordic Seas last glacial radiocarbon ocean ventilation |
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 14 C 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 14 C ventilation ages that are derived from dating different benthic foraminiferal species: Pyrgo and other miliolid species yield ventilation ages >6000 14 C years, while all other species reveal ventilation ages <2000 14 C years. These data either suggest subcentennial, regional, circulation changes or that miliolid-based 14 C 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 |
Ezat, Mohamed M. Rasmussen, Tine L. Thornalley, David J. R. Olsen, Jesper Skinner, Luke C. Honisch, Barbel Groeneveld, Jeroen |
author_facet |
Ezat, Mohamed M. Rasmussen, Tine L. Thornalley, David J. R. Olsen, Jesper Skinner, Luke C. Honisch, Barbel Groeneveld, Jeroen |
author_sort |
Ezat, Mohamed M. |
title |
Ventilation history of Nordic Seas overflows during the last (de)glacial period revealed by species-specific benthic foraminiferal 14 C dates |
title_short |
Ventilation history of Nordic Seas overflows during the last (de)glacial period revealed by species-specific benthic foraminiferal 14 C dates |
title_full |
Ventilation history of Nordic Seas overflows during the last (de)glacial period revealed by species-specific benthic foraminiferal 14 C dates |
title_fullStr |
Ventilation history of Nordic Seas overflows during the last (de)glacial period revealed by species-specific benthic foraminiferal 14 C dates |
title_full_unstemmed |
Ventilation history of Nordic Seas overflows during the last (de)glacial period revealed by species-specific benthic foraminiferal 14 C dates |
title_sort |
ventilation history of nordic seas overflows during the last (de)glacial period revealed by species-specific benthic foraminiferal 14 c dates |
publishDate |
2017 |
url |
https://pure.au.dk/portal/en/publications/7685acac-32bf-46b1-bd83-6c85b32c7f39 https://doi.org/10.1002/2016PA003053 http://www.scopus.com/inward/record.url?scp=85013382096&partnerID=8YFLogxK |
geographic |
Arctic Arctic Ocean Norwegian Sea |
geographic_facet |
Arctic Arctic Ocean Norwegian Sea |
genre |
Arctic Arctic Ocean Climate change Foraminifera* ice core Iceland Nordic Seas North Atlantic Norwegian Sea |
genre_facet |
Arctic Arctic Ocean Climate change Foraminifera* ice core Iceland Nordic Seas North Atlantic Norwegian Sea |
op_source |
Ezat , M M , Rasmussen , T L , Thornalley , D J R , Olsen , J , Skinner , L C , Honisch , B & Groeneveld , J 2017 , ' Ventilation history of Nordic Seas overflows during the last (de)glacial period revealed by species-specific benthic foraminiferal 14 C dates ' , Paleoceanography , vol. 32 , no. 2 , pp. 172-181 . https://doi.org/10.1002/2016PA003053 |
op_relation |
https://pure.au.dk/portal/en/publications/7685acac-32bf-46b1-bd83-6c85b32c7f39 |
op_rights |
info:eu-repo/semantics/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_ |
1790597383666532352 |