Geochemical proxies of North American freshwater routing during the Younger Dryas cold event
Author Posting. © The Authors, 2006. This is the author's version of the work. It is posted here by permission of National Academy of Sciences for personal use, not for redistribution. The definitive version was published in Proceedings of the National Academy of Sciences 104 (2007): 6556-6561,...
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ftwhoas:oai:darchive.mblwhoilibrary.org:1912/1574 2023-05-15T18:01:03+02:00 Geochemical proxies of North American freshwater routing during the Younger Dryas cold event Carlson, Anders E. Clark, Peter U. Haley, Brian A. Klinkhammer, Gary P. Simmons, Kathleen Brook, Edward J. Meissner, Katrin J. 2006-12-19 application/pdf https://hdl.handle.net/1912/1574 en_US eng https://doi.org/10.1073/pnas.0611313104 https://hdl.handle.net/1912/1574 Preprint 2006 ftwhoas https://doi.org/10.1073/pnas.0611313104 2022-05-28T22:57:17Z Author Posting. © The Authors, 2006. This is the author's version of the work. It is posted here by permission of National Academy of Sciences for personal use, not for redistribution. The definitive version was published in Proceedings of the National Academy of Sciences 104 (2007): 6556-6561, doi:10.1073/pnas.0611313104. The Younger Dryas cold interval represents a time when much of the Northern Hemisphere cooled from ~12.9 to 11.5 kiloyears before present. The cause of this event, which has long been viewed as the canonical example of abrupt climate change, was initially attributed to the routing of freshwater to the St. Lawrence River with an attendant reduction in Atlantic meridional overturning circulation. However, this mechanism has recently been questioned because current proxies and dating techniques have been unable to confirm that eastward routing with an increase in freshwater flux occurred during the Younger Dryas. Here we use new geochemical proxies (ΔMg/Ca, U/Ca & 87Sr/86Sr) measured in planktonic foraminifera at the mouth of the St. Lawrence Estuary as tracers of freshwater sources to further evaluate this question. Our proxies, combined with planktonic δ18Oseawater and δ13C, confirm that routing of runoff from western Canada to the St. Lawrence River occurred at the start of the Younger Dryas, with an attendant increase in freshwater flux of 0.06 ± 0.02 Sverdrup (1 Sverdrup (Sv) = 106 m3 s-1). This base discharge increase is sufficient to have reduced Atlantic meridional overturning circulation and caused the Younger Dryas cold interval. In addition, our data indicate subsequent fluctuations in the freshwater flux to the St. Lawrence River of ~0.06 to 0.12 Sv, thus explaining the variability in the overturning circulation and climate during the Younger Dryas. This research was funded by the NSF Paleoclimate Program (P.U.C.) and the NSF (G.P.K.). Report Planktonic foraminifera Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) Canada Lawrence River ENVELOPE(-115.002,-115.002,58.384,58.384) Proceedings of the National Academy of Sciences 104 16 6556 6561 |
institution |
Open Polar |
collection |
Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) |
op_collection_id |
ftwhoas |
language |
English |
description |
Author Posting. © The Authors, 2006. This is the author's version of the work. It is posted here by permission of National Academy of Sciences for personal use, not for redistribution. The definitive version was published in Proceedings of the National Academy of Sciences 104 (2007): 6556-6561, doi:10.1073/pnas.0611313104. The Younger Dryas cold interval represents a time when much of the Northern Hemisphere cooled from ~12.9 to 11.5 kiloyears before present. The cause of this event, which has long been viewed as the canonical example of abrupt climate change, was initially attributed to the routing of freshwater to the St. Lawrence River with an attendant reduction in Atlantic meridional overturning circulation. However, this mechanism has recently been questioned because current proxies and dating techniques have been unable to confirm that eastward routing with an increase in freshwater flux occurred during the Younger Dryas. Here we use new geochemical proxies (ΔMg/Ca, U/Ca & 87Sr/86Sr) measured in planktonic foraminifera at the mouth of the St. Lawrence Estuary as tracers of freshwater sources to further evaluate this question. Our proxies, combined with planktonic δ18Oseawater and δ13C, confirm that routing of runoff from western Canada to the St. Lawrence River occurred at the start of the Younger Dryas, with an attendant increase in freshwater flux of 0.06 ± 0.02 Sverdrup (1 Sverdrup (Sv) = 106 m3 s-1). This base discharge increase is sufficient to have reduced Atlantic meridional overturning circulation and caused the Younger Dryas cold interval. In addition, our data indicate subsequent fluctuations in the freshwater flux to the St. Lawrence River of ~0.06 to 0.12 Sv, thus explaining the variability in the overturning circulation and climate during the Younger Dryas. This research was funded by the NSF Paleoclimate Program (P.U.C.) and the NSF (G.P.K.). |
format |
Report |
author |
Carlson, Anders E. Clark, Peter U. Haley, Brian A. Klinkhammer, Gary P. Simmons, Kathleen Brook, Edward J. Meissner, Katrin J. |
spellingShingle |
Carlson, Anders E. Clark, Peter U. Haley, Brian A. Klinkhammer, Gary P. Simmons, Kathleen Brook, Edward J. Meissner, Katrin J. Geochemical proxies of North American freshwater routing during the Younger Dryas cold event |
author_facet |
Carlson, Anders E. Clark, Peter U. Haley, Brian A. Klinkhammer, Gary P. Simmons, Kathleen Brook, Edward J. Meissner, Katrin J. |
author_sort |
Carlson, Anders E. |
title |
Geochemical proxies of North American freshwater routing during the Younger Dryas cold event |
title_short |
Geochemical proxies of North American freshwater routing during the Younger Dryas cold event |
title_full |
Geochemical proxies of North American freshwater routing during the Younger Dryas cold event |
title_fullStr |
Geochemical proxies of North American freshwater routing during the Younger Dryas cold event |
title_full_unstemmed |
Geochemical proxies of North American freshwater routing during the Younger Dryas cold event |
title_sort |
geochemical proxies of north american freshwater routing during the younger dryas cold event |
publishDate |
2006 |
url |
https://hdl.handle.net/1912/1574 |
long_lat |
ENVELOPE(-115.002,-115.002,58.384,58.384) |
geographic |
Canada Lawrence River |
geographic_facet |
Canada Lawrence River |
genre |
Planktonic foraminifera |
genre_facet |
Planktonic foraminifera |
op_relation |
https://doi.org/10.1073/pnas.0611313104 https://hdl.handle.net/1912/1574 |
op_doi |
https://doi.org/10.1073/pnas.0611313104 |
container_title |
Proceedings of the National Academy of Sciences |
container_volume |
104 |
container_issue |
16 |
container_start_page |
6556 |
op_container_end_page |
6561 |
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1766170382954397696 |