Western Tropical North Atlantic Foraminifera-based Nd Isotope Data Since the Last Glacial Maximum Huang, K.-F.; Oppo, D.W.; Curry, W.B. Huang, K.-F. Oppo, D.W. Curry, W.B. Heinrich Events Younger Dryas earth science/paleoclimate/paleoceanography (age,null,null,calendar year before present,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (epsilon neodymium,planktic foraminifer,null,epsilon unit,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,reference period: 0-23 kyr BP) earth science/paleoclimate/paleoceanography (epsilon neodymium,planktic foraminifer,two standard deviations,epsilon unit,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,reference period: 0-23 kyr BP) earth science/paleoclimate/paleoceanography (depth,null,null,centimeter,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleocean (KNR197-3-9GGC>LATITUDE 7.93>LONGITUDE -53.575167) (KNR197-3-46CDH>LATITUDE 7.836>LONGITUDE -53.663333) (KNR197-3-25GGC>LATITUDE 7.7045>LONGITUDE -53.785333) Antarctic Intermediate Water (AAIW) is a key player in the global ocean circulation, contributing to the upper limb of the Atlantic Meridional Overturning Circulation (AMOC), and influencing interhemispheric heat exchange and the distribution of salinity, nutrients and carbon. However, the deglacial history of AAIW flow into the North Atlantic is controversial. Here we present a multicore-top neodymium isotope calibration, which confirms the ability of unclean foraminifera to faithfully record bottom water neodymium isotopic composition (eNd) values in their authigenic coatings. We then present the first foraminifera-based reconstruction of eNd from three sediment cores retrieved from within modern AAIW, in the western tropical North Atlantic. Our records reveal similar glacial and interglacial contributions of AAIW, and a pronounced decrease in the AAIW fraction during North Atlantic deglacial cold episodes, Heinrich Stadial 1 (HS1) and Younger Dryas (YD). Our results suggest two separate phases of reduced fraction of AAIW in the tropical Atlantic during HS1, with a greater reduction during early HS1. If a reduction in AAIW fraction also reflects reduced AMOC strength, these finding may explain why, in many regions, there are two phases of hydrologic change within HS1, and why atmospheric CO2 rose more rapidly during early than late HS1. Our result suggesting less flow of AAIW into the Atlantic during North Atlantic cold events contrasts with evidence from the Pacific, where intermediate-depth eNd records may indicate increased flow of AAIW into the Pacific during the these same events. Antiphased eNd behavior between intermediate depths of the North Atlantic and Pacific implies that the flow of AAIW into Atlantic and Pacific seesawed during the last deglaciation. STUDY NOTES: Keywords from journal: Nd isotopes; Antarctic intermediate water; Atlantic meridional overturning circulation; deglacial variability; North Atlantic cold events NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Huang, K.-F. Investigator : Oppo, D.W. Investigator : Curry, W.B. 2014-03-17 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/16156 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/huang2014/huang2014-25ggc.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/huang2014/huang2014-46cdh.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/huang2014/huang2014-9ggc.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/huang2014/huang2014-25ggc.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/huang2014/huang2014-46cdh.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/huang2014/huang2014-9ggc.txt English https://www.ncdc.noaa.gov/paleo/study/16156 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/huang2014/huang2014-25ggc.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/huang2014/huang2014-46cdh.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/huang2014/huang2014-9ggc.txt Huang, K.-F., D.W. Oppo, and W.B. Curry2014Decreased influence of Antarctic intermediate water in the tropical Atlantic during North Atlantic cold eventsEarth and Planetary Science Letters389200-20810.1016/j.epsl.2013.12.037 START YEAR: 22600 cal yr BP * END YEAR: 70 cal yr BP -53.785333 7.7045 -53.575167 7.93