# Tropical North Atlantic Nd Isotopic Ratio Data over the last 22,000 Years #----------------------------------------------------------------------- # World Data Center for Paleoclimatology, Boulder # and # NOAA Paleoclimatology Program #----------------------------------------------------------------------- # NOTE: Please cite original publication, online resource and date accessed when using this data. # If there is no publication information, please cite Investigator, title, online resource and date accessed. # # Online_Resource: http://www.ncdc.noaa.gov/paleo/study/17373 # Online_Resource: ftp://ftp.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/xie2014/xie2014-26jpc.txt # # Archive: Paleoceanography # #-------------------------------- # Contribution_Date # Date: 2014-10-27 #-------------------------------- # Title: Tropical North Atlantic Nd Isotopic Ratio Data over the last 22,000 Years #-------------------------------- # Investigators: Xie, Ruifang C.; Marcantonio, Franco; Schmidt, M.W. #-------------------- # Description and Notes: # Description: # #-------------------- # Publication # Authors: Xie, R.C., F. Marcantonio, and M.W. Schmidt # Journal_Name: Geochimica et Cosmochimica acta # Published_Title: Reconstruction of intermediate water circulation in the tropical North Atlantic during the past 22,000 years # Published_Date_or_Year: 2014 # Volume: 140 # Report Number: # Pages: 455-467 # DOI: 10.1016/j.gca.2014.05.041 # Abstract: Decades of paleoceanographic studies have reconstructed a well-resolved water mass structure for the deep Atlantic Ocean during the Last Glacial Maximum (LGM). However, the variability of intermediate water circulation in the tropics over the LGM and deglacial abrupt climate events is still largely debated. This study aims to reconstruct intermediate northern- and southern-sourced water circulation in the tropical North Atlantic during the past 22 kyr and attempts to confine the boundary between Antarctic Intermediate Water (AAIW) and northern-sourced intermediate water (i.e., upper North Atlantic Deep Water (NADW) or Glacial North Atlantic Intermediate Water) in the past. High-resolution Nd isotopic compositions of fish debris and acid-reductive leachate of bulk sediment in core VM12-107 (1079 m depth) from the Southern Caribbean are not in agreement. We suggest that the leachate method does not reliably extract the Nd isotopic compositions of seawater at this location, and that it needs to be tested in more detail in various oceanic settings. The fish debris εNd values display a general decrease from the early deglaciation to the end of the Younger Dryas, followed by a greater drop toward less radiogenic values into the early Holocene. We propose a potentially more radiogenic glacial northern endmember water mass and interpret this pattern as recording a recovery of the upper NADW during the last deglaciation. Comparing our new fish debris Nd isotope data to authigenic Nd isotope studies in the Florida Straits (546 and 751 m depth), we propose that both glacial and deglacial AAIW do not penetrate beyond the lower depth limit of modern AAIW in the tropical Atlantic. #-------------------------------- # Funding_Agency: # Funding_Agency_Name: # Grant: #-------------------------------- # Site Information: # Site_Name: KNR166-2-26JPC # Location: North Atlantic Ocean # Northernmost_Latitude: 24.327 # Southernmost_Latitude: 24.327 # Easternmost_Longitude: -83.252333 # Westernmost_Longitude: -83.252333 # Elevation: -546 #-------------------------------- # Data Collection # Collection_Name K166-2-26JPC Nd FishDebris X14 # Oldest_Year: 22500 # Most_Recent_Year: 9100 # Time_Unit: cal yr BP # Core_Length # Notes: #-------------------------------- # Chronology #-------------------------------- # Variables # # Data variables follow (have double marker- "##") # Data line variables format: Variables list, one per line, shortname-tab-nine components: what, material, error, units, seasonality, archive, detail, method, C or N for Character or Numeric data) ## depth_top depth top of sample,,,cm,,,,,N ## depth_bottom depth bottom of sample,,,cm,,,,,N ## age_calkaBP Age,,,calendar kiloyears before present,,,,,N ## 143Nd/144Nd-fd Neodymium 143/Neodymium 144 ratio,,, ,,paleoceanography,fish debris,,N ## 143Nd/144Nd-fd_err Neodymium 143/Neodymium 144,,2s error, ,,paleoceanography,fish debris,,N ## e-Nd-fd epsilon-Neodymium,,,  ,,paleoceanography,fish debris,,N ## e-Nd-fd_std epsilon-Neodymium standard deviation,,, ,,paleoceanography,fish debris,,N # Data: # Missing Value: NaN depth_top depth_bottom age_calkaBP 143Nd/144Nd-fd 143Nd/144Nd-fd_err e-Nd-fd e-Nd-fd_std 166 166.5 9.1 0.512157 19 -9.4 0.4 208 208.5 10.2 0.512172 26 -9.1 0.5 240 240.5 10.7 0.512119 11 -10.1 0.2 300 300.5 11.2 0.512143 17 -9.7 0.3 645 645.5 13.7 0.512139 21 -9.7 0.4 654 654.5 14.0 0.512174 11 -9.0 0.2 660 660.5 14.2 0.512162 19 -9.3 0.4 690 690.5 15.3 0.512150 11 -9.5 0.2 720 720.5 16.6 0.512130 10 -9.9 0.2 750 750.5 18.2 0.512167 11 -9.2 0.2 766.5 767 19.1 0.512168 15 -9.2 0.3 780 780.5 19.9 0.512183 12 -8.9 0.2 802.5 803 21.1 0.512175 10 -9.0 0.2 826 826.5 22.5 0.512161 8 -9.3 0.2