noaa-ocean-26730 Late glacial to Holocene sortable silt records from the southwestern Labrador Sea Hoffmann, S.S.; Dalsing, R.E.; Murphy, S.C. Late glacial to Holocene sortable silt records from the southwestern Labrador Sea 2019-05-06 NCDC-Paleoclimatology ONLINE Files Pending https://www.ncdc.noaa.gov/paleo/study/26730 Investigator S.S. Hoffmann Investigator R.E. Dalsing Investigator S.C. Murphy earth science paleoclimate paleocean geochemistry earth science paleoclimate paleocean oxygen isotopes earth science paleoclimate paleocean physical properties geoscientificInformation 21342 cal yr BP 750 cal yr BP Complete 49 49.244 -48.9877 -45.017 Ocean Atlantic Ocean North Atlantic Ocean V23-18, KN158-4-27 and 28>LATITUDE >LONGITUDE 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

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Boulder CO 80305-3328 USA online ASCII Hoffmann, S.S., Dalsing, R.E., and Murphy, S.C. 2019 Quaternary Science Reviews 206 99-110 10.1016/j.quascirev.2018.12.028

The Labrador Sea is a vital region for the Atlantic Meridional Overturning Circulation (AMOC), where overflow waters from the Nordic Seas mix with locally produced Labrador Sea Water, before exiting to the interior of the Atlantic Ocean. The dynamical sedimentary proxy of mean sortable silt size (SS) can give information on past changes in deep water circulation speed and the strength of AMOC. We have produced (SS) records from two core sites at depths between 1500 and 2000 m on the continental slope east of Newfoundland, to reconstruct changes in intermediate depth water circulation speed, including Glacial North Atlantic Intermediate Water and Labrador Sea Water over the past 22,000 years. Increases in (SS) appear to coincide with much of the deglaciation as well as the mid-late Holocene. End-member modeling suggests that ice-rafted debris (IRD) is an important factor in interpreting (SS) during the deglaciation. We find that a robust increase in (SS) is likely unrelated to IRD during the past 5 ka, and probably reflects increased flow at intermediate depths due to local production of LSW strengthening as Nordic Seas overflows weakened at this depth. Our results highlight both the complications of producing (SS) records in IRD-rich, slope environments and the promise that this proxy nevertheless has for reconstructing dynamical changes in deep ocean currents. STUDY NOTES: Site metadata: KN158-4-27 (49.244 N, -48.9877 W, -1846 m, core length: 2.13); KN158-4-28 (49.2433 N, -48.9872 W, -1828 m, core length: 0.36); V23-18 (49 N, -45.017 W, -1593 m, core length: 4.05) Provided Keywords: sediment grain size, sediment geochemistry

GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hoffmann2019/hoffmann2019-ca_sr.txt NOAA Template File; V23-18, KN158-4-27/28 Ca/Sr Data GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hoffmann2019/hoffmann2019-d18o.txt NOAA Template File; V23-18, KN158-4-27/28 d18O Data GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hoffmann2019/hoffmann2019-em.txt NOAA Template File; V23-18, KN158-4-27/28 Silt and Grain Size Data GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hoffmann2019/hoffmann2019-coarse.txt NOAA Template File; V23-18, KN158-4-27/28 Coarse Fraction Data USA/NOAA DIF Version 9.8.4 2019-05-09 2019-05-09