noaa-ocean-8457 St. Lawrence Estuary Younger Dryas Geochemical Data Carlson, A.E.; Clark, P.U.; Haley, B.A.; Klinkhammer, G.P.; Simmons, K.R.; Brook, E.J.; Meissner, K.J. St. Lawrence Estuary Younger Dryas Geochemical Data 2007-01-01 NCDC-Paleoclimatology ONLINE Files Pending https://www.ncdc.noaa.gov/paleo/study/8457 Investigator A.E. Carlson Investigator P.U. Clark Investigator B.A. Haley Investigator G.P. Klinkhammer Investigator K.R. Simmons Investigator E.J. Brook Investigator K.J. Meissner earth science paleoclimate paleocean geochemistry earth science paleoclimate paleocean trace metals in carbonates earth science paleoclimate paleocean oxygen isotopes earth science paleoclimate paleocean carbon isotopes earth science paleoclimate paleocean reconstruction earth science paleoclimate paleocean age control geoscientificInformation 14872 cal yr BP 0 cal yr BP Complete 44.657 45.852 -57.626 -55.619 -1381 -473 Ocean Atlantic Ocean North Atlantic Ocean HU90031-044>LATITUDE 44.657>LONGITUDE -55.619 Ocean Atlantic Ocean North Atlantic Ocean HU90031-047>LATITUDE 45.852>LONGITUDE -57.626 None Please cite original publication, online resource, dataset and publication DOIs (where available), and date accessed when using downloaded data. If there is no publication information, please cite investigator, title, online resource, and date accessed. The appearance of external links associated with a dataset does not constitute endorsement by the Department of Commerce/National Oceanic and Atmospheric Administration of external Web sites or the information, products or services contained therein. For other than authorized activities, the Department of Commerce/NOAA does not exercise any editorial control over the information you may find at these locations. These links are provided consistent with the stated purpose of this Department of Commerce/NOAA Web site. English DOC/NOAA/NESDIS/NCEI National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce https://www.ncdc.noaa.gov/data-access/paleoclimatology-data DATA Center Contact Bruce Bauer bruce.a.bauer@noaa.gov paleo@noaa.gov 303-497-6280 303-497-6513

325 Broadway, E/NE31

Boulder CO 80305-3328 USA online ASCII Carlson, A.E., P.U. Clark, B.A. Haley, G.P. Klinkhammer, Simmons, K., E.J. Brook, and K.J. Meissner. 2007. Geochemical proxies of North American freshwater routing during the Younger Dryas cold event.Proceedings of the National Academy of Sciences, 104(16), 6556-6561.

The Younger Dryas cold interval represents a time when much of the Northern Hemisphere cooled from ~12.9 to 11.5 kiloyears B.P. 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 (ŋMg/Ca, U/Ca, and 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 ŋ18Oseawater and ŋ13C, 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 ą 0.02 Sverdrup (1 Sverdrup = 10^6 m3ˇs-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 ~0.06-0.12 Sverdrup, thus explaining the variability in the overturning circulation and climate during the Younger Dryas.

GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/by_contributor/carlson2007 USA/NOAA DIF Version 9.8.4 2018-12-11 2018-12-11