Central Arctic Sedimentary 231Pa/230Th Ratios from the Past 35,000 Years Hoffmann, S.S.; McManus, J.F.; Curry, W.B.; Brown-Leger, S. Hoffmann, S.S. McManus, J.F. Curry, W.B. Brown-Leger, S. earth science/paleoclimate/paleoceanography (230Th,sediment,two standard error,disintegration per minute per gram,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,null) earth science/paleoclimate/paleoceanography (231Pa excess,sediment,two standard error,disintegration per minute per gram,null,paleoceanography,corrected,inductively-coupled plasma mass spectrometry,N,null) earth science/paleoclimate/paleoceanography (231Pa/230Th excess,sediment,null,dimensionless,null,paleoceanography,corrected,null,N,excess corrections assuming 238U/232Th = 0.5) earth science/paleoclimate/paleoceanography (231Pa/230Th excess,sediment,null,dimensionless,null,paleoceanography,corrected,null,N,excess corrections assuming 238U/232Th = 0.5 ) earth science/paleoclimate/paleoceanography (age,null,null,calendar kiloyear before present,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (230Th excess,sediment,null,disintegration per minute per gram,null,paleoceanography,corrected,inductively-coupled plasma mass spectrometry,N,null) earth science/paleoclimate/paleoceanography (238U,sediment,null,disintegration per minute per gram,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,null) earth science/paleoclimate/paleoceanography (232Th,sediment,two standard error,disintegration per minute per gram,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,null) earth science/paleoclimate/paleoceanography (231Pa/230Th excess,sediment,one standard error,dimensionless,null,paleoceanography,averaged|corrected,null,N,null) earth science/paleoclimate/paleoceanography (232Th,sediment,null,disintegration per minute per gram,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,null) earth science/paleoclimate/paleoceanography (231Pa/230Th excess,sediment,null,dimensionless,null,paleoceanography,corrected,null,N,excess corrections assuming 238U/232Th = 0.7) earth science/paleoclimate/paleoceanography (230Th excess,sediment,null,gram per square meter per kiloyear,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (231Pa/230Th excess,sediment,null,dimensionless,null,paleoceanography,averaged|corrected,null,N,null) earth science/paleoclimate/paleoceanography (231Pa,sediment,null,disintegration per minute per gram,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,null) earth science/paleoclimate/paleoceanography (238U/232Th,sediment,null,dimensionless,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (231Pa/230Th excess,sediment,null,dimensionless,null,paleoceanography,corrected,null,N,excess corrections assuming 238U/232Th = 0.7 ) earth science/paleoclimate/paleoceanography (230Th,sediment,null,disintegration per minute per gram,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,null) earth science/paleoclimate/paleoceanography (231Pa excess,sediment,null,disintegration per minute per gram,null,paleoceanography,corrected,inductively-coupled plasma mass spectrometry,N,null) earth science/paleoclimate/paleoceanography (231Pa,sediment,two standard error,disintegration per minute per gram,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,null) earth science/paleoclimate/paleoceanography (238U,sediment,two standard error,disintegration per minute per gram,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,null) earth science/paleoclimate/paleoceanography (230Th excess,sediment,two standard error,disintegration per minute per gram,null,paleoceanography,corrected,inductively-coupled plasma mass spectrometry,N,null) earth science/paleoclimate/paleoceanography (depth,null,null,centimeter,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (238U/232Th,sediment,two standard error,dimensionless,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleocean (PL94-AR BC20>LATITUDE 83.18>LONGITUDE 174.09) (PL94-AR BC08>LATITUDE 78.13>LONGITUDE -176.88) (PL94-AR BC16>LATITUDE 80.33>LONGITUDE -178.72) (PL94-AR BC26>LATITUDE 88.8>LONGITUDE 143.48) (PL94-AR BC28>LATITUDE 88.87>LONGITUDE 140.18) (PL94-AR BC17>LATITUDE 81.27>LONGITUDE 178.87) (PL94-AR BC32>LATITUDE 85.72>LONGITUDE 37.75) The Arctic Ocean has an important role in Earth’s climate, both through surface processes such as sea-ice formation and transport, and through the production and export of waters at depth that contribute to the global thermohaline circulation. Deciphering the deep Arctic Ocean’s palaeo-oceanographic history is a crucial part of understanding its role in climatic change. Here we show that sedimentary ratios of the radionuclides thorium-230 (230Th) and protactinium-231 (231Pa), which are produced in sea water and removed by particle scavenging on timescales of decades to centuries, respectively, record consistent evidence for the export of 231Pa from the deep Arctic and may indicate continuous deepwater exchange between the Arctic and Atlantic oceans throughout the past 35,000 years. Seven well-dated box-core records provide a comprehensive overview of 231Pa and 230Th burial in Arctic sediments during glacial, deglacial and interglacial conditions. Sedimentary 231Pa/230Th ratios decrease nearly linearly with increasing water depth above the core sites, indicating efficient particle scavenging in the upper water column and greater influence of removal by lateral transport at depth. Although the measured 230Th burial is in balance with its production in Arctic sea water, integrated depth profiles for all time intervals reveal a deficit in 231Pa burial that can be balanced only by lateral export in the water column. Because no enhanced sink for 231Pa has yet been found in the Arctic, our records suggest that deep-water exchange through the Fram strait may export 231Pa. Such export may have continued for the past 35,000 years, suggesting a century-scale replacement time for deep waters in the Arctic Ocean since the most recent glaciation and a persistent contribution of Arctic waters to the global ocean circulation. STUDY NOTES: U-series radionuclide records from seven Arctic sediment cores, with excess 231Pa/230Th ratios interpreted as indicators of 231Pa export in the water column. Age models are from calibrated radiocarbon measurements on polar foraminifer species N. pachyderma (sinistral). NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Hoffmann, S.S. Investigator : McManus, J.F. Investigator : Curry, W.B. Investigator : Brown-Leger, S. 2014-07-10 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/16914 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hoffmann2013/hoffmann2013-bc20.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hoffmann2013/hoffmann2013-bc17.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hoffmann2013/hoffmann2013-bc08.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hoffmann2013/hoffmann2013-bc16.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hoffmann2013/hoffmann2013-bc32.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hoffmann2013/hoffmann2013-bc28.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hoffmann2013/hoffmann2013-bc26.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hoffmann2013/hoffmann2013-bc20.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hoffmann2013/hoffmann2013-bc17.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hoffmann2013/hoffmann2013-bc08.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hoffmann2013/hoffmann2013-bc16.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hoffmann2013/hoffmann2013-bc32.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hoffmann2013/hoffmann2013-bc28.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hoffmann2013/hoffmann2013-bc26.txt English https://www.ncdc.noaa.gov/paleo/study/16914 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hoffmann2013/hoffmann2013-bc20.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hoffmann2013/hoffmann2013-bc17.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hoffmann2013/hoffmann2013-bc08.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hoffmann2013/hoffmann2013-bc16.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hoffmann2013/hoffmann2013-bc32.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hoffmann2013/hoffmann2013-bc28.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hoffmann2013/hoffmann2013-bc26.txt Hoffmann, S.S., J.F. McManus, W.B. Curry, and L.S. Brown-Leger2013Persistent export of 231Pa from the deep central Arctic Ocean over the past 35,000 yearsNature497603-60610.1038/nature12145 START YEAR: 45920 cal yr BP * END YEAR: 1590 cal yr BP -178.72 78.13 178.87 88.87