# South Atlantic 24,000 Year Neodymium Isotope Data #----------------------------------------------------------------------- # World Data Service for Paleoclimatology, Boulder # and # NOAA Paleoclimatology Program # National Centers for Environmental Information (NCEI) #----------------------------------------------------------------------- # Template Version 2.0 # NOTE: Please cite Publication, and Online_Resource and date accessed when using these data. # If there is no publication information, please cite Investigators, Title, and Online_Resource and date accessed. # # Online_Resource: https://www.ncdc.noaa.gov/paleo/study/20673 # Online_Resource: http://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/howe2016/howe2016knr159-5-36ggc.txt # # Original_Source_URL: # # Description/Documentation lines begin with # # Data lines have no # # # Archive: Paleoceanography # # Parameter_Keywords: geochemistry #-------------------- # Contribution_Date # Date: 2016-10-27 #-------------------- # Title # Study_Name: South Atlantic 24,000 Year Neodymium Isotope Data #-------------------- # Investigators # Investigators: Howe, J.N.W.; Piotrowski, A.M.; Oppo, D.W.; Huang, K.-F.; Mulitza, S.; Chiessi, C.M.; Blusztajn, J. #-------------------- # Description_and_Notes # Description: Neodymium isotope (143Nd/144Nd and eNd) data from three South Atlantic sediment cores. For all three cores, # measurements on uncleaned planktonic foraminifera are provided. For GEOB2107-3 and GEOB2104-3, measurements on # leachates are also provided. #-------------------- # Publication # Authors: Jacob N.W. Howe, Alexander M. Piotrowski, Delia W. Oppo, Kuo-Fang Huang, Stefan Mulitza, Cristiano M. Chiessi, Jurek Blusztajn # Published_Date_or_Year: 2016-10-05 # Published_Title: Antarctic intermediate water circulation in the South Atlantic over the past 25,000 years # Journal_Name: Paleoceanography # Volume: # Edition: # Issue: # Pages: # Report_Number: # DOI: 10.1002/2016PA002975 # Online_Resource: http://onlinelibrary.wiley.com/doi/10.1002/2016PA002975/full # Full_Citation: # Abstract: Antarctic Intermediate Water is an essential limb of the Atlantic meridional overturning circulation that redistributes heat and nutrients within the Atlantic Ocean. Existing reconstructions have yielded conflicting results on the history of Antarctic Intermediate Water penetration into the Atlantic across the most recent glacial termination. In this study we present leachate, foraminiferal, and detrital neodymium isotope data from three intermediate-depth cores collected from the southern Brazil margin in the South Atlantic covering the past 25 kyr. These results reveal that strong chemical leaching following decarbonation does not extract past seawater neodymium composition in this location. The new foraminiferal records reveal no changes in seawater Nd isotopes during abrupt Northern Hemisphere cold events at these sites. We therefore conclude that there is no evidence for greater incursion of Antarctic Intermediate Water into the South Atlantic during either the Younger Dryas or Heinrich Stadial 1. We do, however, observe more radiogenic Nd isotope values in the intermediate-depth South Atlantic during the mid-Holocene. This radiogenic excursion coincides with evidence for a southward shift in the Southern Hemisphere westerlies that may have resulted in a greater entrainment of radiogenic Pacific-sourced water during intermediate water production in the Atlantic sector of the Southern Ocean. Our intermediate-depth records show similar values to a deglacial foraminiferal Nd isotope record from the deep South Atlantic during the Younger Dryas but are clearly distinct during the Last Glacial Maximum and Heinrich Stadial 1, demonstrating that the South Atlantic remained chemically stratified during Heinrich Stadial 1. #------------------ # Publication # Authors: K.R. Hendry, L.F. Robinson, M.P. Meredith, S. Mulitza, C.M. Chiessi and H. Arz # Published_Date_or_Year: 2012-02-01 # Published_Title: Abrupt changes in high-latitude nutrient supply to the Atlantic during the last glacial cycle # Journal_Name: Geology # Volume: 40 # Edition: # Issue: 2 # Pages: 123-126 # Report_Number: # DOI: 10.1130/G32779.1 # Online_Resource: http://geology.gsapubs.org/content/40/2/123 # Full_Citation: # Abstract: The supply of nutrients to the low-latitude thermocline is largely controlled by intermediate-depth waters formed at the surface in the high southern latitudes. Silicic acid is an essential macronutrient for diatoms, which are responsible for a significant portion of marine carbon export production. Changes in ocean circulation, such as those observed during the last deglaciation, would influence the nutrient composition of the thermocline and, therefore, the relative abundance of diatoms in the low latitudes. Here we present the first record of the silicic acid content of the Atlantic over the last glacial cycle. Our results show that at intermediate depths of the South Atlantic, the silicic acid concentration was the same at the Last Glacial Maximum (LGM) as it is today, overprinted by high silicic acid pulses that coincided with abrupt changes in ocean and atmospheric circulation during Heinrich Stadials and the Younger Dryas. We suggest these pulses were caused by changes in intermediate water formation resulting from shifts in the subpolar hydrological cycle, with fundamental implications for the nutrient supply to the Atlantic. #------------------ # Publication # Authors: D.C. Lund, A.C. Tessin, J.L. Hoffman, A. Schmittner # Published_Date_or_Year: 2015-05-01 # Published_Title: Southwest Atlantic water mass evolution during the last deglaciation # Journal_Name: Paleoceanography # Volume: 30 # Edition: # Issue: # Pages: 477-494 # Report_Number: # DOI: 10.1002/2014PA002657 # Online_Resource: http://onlinelibrary.wiley.com/doi/10.1002/2014PA002657/abstract # Full_Citation: # Abstract: The rise in atmospheric CO2 during Heinrich Stadial 1 (HS1; 14.5-17.5 kyr B.P.) may have been driven by the release of carbon from the abyssal ocean. Model simulations suggest that wind-driven upwelling in the Southern Ocean can liberate 13C-depleted carbon from the abyss, causing atmospheric CO2 to increase and the d13C of CO2 to decrease. One prediction of the Southern Ocean hypothesis is that water mass tracers in the deep South Atlantic should register a circulation response early in the deglaciation. Here we test this idea using a depth transect of 12 cores from the Brazil Margin. We show that records below 2300 m remained 13C-depleted until 15 kyr B.P. or later, indicating that the abyssal South Atlantic was an unlikely source of light carbon to the atmosphere during HS1. Benthic d18O results are consistent with abyssal South Atlantic isolation until 15 kyr B.P., in contrast to shallower sites. The depth dependent timing of the d18O signal suggests that correcting d18O for ice volume is problematic on glacial terminations. New data from 2700 to 3000 m show that the deep SW Atlantic was isotopically distinct from the abyss during HS1. As a result, we find that mid-depth d13C minima were most likely driven by an abrupt drop in d13C of northern component water. Low d13C at the Brazil Margin also coincided with an ~80 per mil decrease in D14C. Our results are consistent with a weakening of the Atlantic meridional overturning circulation and point toward a northern hemisphere trigger for the initial rise in atmospheric CO2 during HS1. #------------------ # Publication # Authors: Paula J Reimer, Edouard Bard, Alex Bayliss, J Warren Beck, Paul G Blackwell, Christopher Bronk Ramsey, Caitlin E Buck, Hai Cheng, R Lawrence Edwards, Michael Friedrich, Pieter M Grootes, Thomas P Guilderson, Haflidi Haflidason, Irka Hajdas, Christine Hatté, Timothy J Heaton, Dirk L Hoffmann, Alan G Hogg, Konrad A Hughen, K Felix Kaiser, Bernd Kromer, Sturt W Manning, Mu Niu, Ron W Reimer, David A Richards, E Marian Scott, John R Southon, Richard A Staff, Christian S M Turney, Johannes van der Plicht # Published_Date_or_Year: 2013-04-01 # Published_Title: IntCal13 and Marine13 Radiocarbon Age Calibration Curves 0-50,000 Years cal BP # Journal_Name: Radiocarbon # Volume: 55 # Edition: # Issue: 4 # Pages: 1869-1887 # Report_Number: # DOI: 10.2458/azu_js_rc.55.16947 # Online_Resource: https://journals.uair.arizona.edu/index.php/radiocarbon/article/view/16947 # Full_Citation: # Abstract: The IntCal09 and Marine09 radiocarbon calibration curves have been revised utilizing newly available and updated data sets from 14C measurements on tree rings, plant macrofossils, speleothems, corals, and foraminifera. The calibration curves were derived from the data using the random walk model (RWM) used to generate IntCal09 and Marine09, which has been revised to account for additional uncertainties and error structures. The new curves were ratified at the 21st International Radiocarbon conference in July 2012 and are available as Supplemental Material at www.radiocarbon.org. The database can be accessed at http://intcal.qub.ac.uk/intcal13/. #------------------ # Funding_Agency # Funding_Agency_Name: Natural Environment Research Council # Grant: NE/K005235/1, NE/F006047/1 #------------------ # Funding_Agency # Funding_Agency_Name: US National Science Foundation # Grant: OCE-1335191 #------------------ # Funding_Agency # Funding_Agency_Name: Rutherford Memorial Scholarship # Grant: #------------------ # Funding_Agency # Funding_Agency_Name: Deutsche Forschungsgemeinschaft # Grant: The Ocean in the Earth System #------------------ # Funding_Agency # Funding_Agency_Name: Sao Paulo Research Foundation (FAPESP) # Grant: N2012/17517-3 #------------------ # Funding_Agency # Funding_Agency_Name: CAPES # Grant: 1976/2014, 564/2015 #------------------ # Site_Information # Site_Name: KNR159-5-36GGC # Location: Ocean>Atlantic Ocean>South Atlantic Ocean # Country: # Northernmost_Latitude: -27.5 # Southernmost_Latitude: -27.5 # Easternmost_Longitude: -46.5 # Westernmost_Longitude: -46.5 # Elevation: -1268 m #------------------ # Data_Collection # Collection_Name: Howe2016KNR159-5-36GGC # Earliest_Year: 22500 # Most_Recent_Year: 3500 # Time_Unit: Cal. Year BP # Core_Length: m # Notes: #------------------ # Chronology_Information # Chronology: # The age model for GeoB2107-3 is based on planktic radiocarbon dates [Heil, 2006] converted to calendar ages # by using the MARINE13 calibration curve [Reimer et al., 2013]. # Age model for KNR159-5-36GGC from Lund et al. (2015). # Age model for GeoB2104-3 uses radioarbon dates in Hendry et al., 2012, supplementary information, converted to # calendar age using the MARINE13 calibration curve [Reimer et al., 2013]. # #---------------- # Variables # # Data variables follow are preceded by "##" in columns one and two. # Data line variables format: Variables list, one per line, shortname-tab-longname-tab-longname components (9 components: what, material, error, units, seasonality, archive, detail, method, C or N for Character or Numeric data) # ## depth_cm depth, , , cm, , , , ,N ## age_calkaBP age, , , calendar Kyears before present, , , , ,N ## 143Nd/144Ndf 143Nd/144Nd ratio, foraminifera, , , , paleoceanography, , ,N ## eNdf Neodymium isotopic composition, foraminifera, , , , paleoceanography, , ,N ## eNdf2S Neodymium isotopic composition 2S error, foraminifera, , , , paleoceanography, , ,N # #---------------- # Data: # Data lines follow (have no #) # Data line format - tab-delimited text, variable short name as header # Missing Values: # depth_cm age_calkaBP 143Nd/144Ndf eNdf eNdf2S 10 3.5 0.512200 -8.53 0.48 40 6.8 0.512206 -8.43 0.48 48 7.9 0.512241 -7.74 0.48 64 10.2 0.512153 -9.47 0.48 70.5 11.9 0.512152 -9.48 0.48 78.5 12.9 0.512134 -9.82 0.48 86.5 13.9 0.512183 -8.88 0.48 94.5 14.3 0.512143 -9.66 0.48 102.5 14.7 0.512140 -9.71 0.48 110.5 15.7 0.512164 -9.26 0.48 118.5 16.1 0.512190 -8.74 0.48 118.5 16.1 0.512147 -9.59 0.52 126.5 16.4 0.512129 -9.93 0.52 134.5 17.0 0.512176 -9.01 0.52 134.5 17.0 0.512187 -8.79 0.48 142.5 18.1 0.512155 -9.41 0.48 150.5 18.3 0.512183 -8.89 0.48 158.5 18.8 0.512181 -8.91 0.48 166.5 19.2 0.512190 -8.73 0.48 174.5 19.7 0.512187 -8.79 0.48 182.5 20.6 0.512176 -9.02 0.52 190.5 22.5 0.512197 -8.60 0.48