Eastern Equatorial Pacific Isotopic Ratios of Sr, Nd, and Pb and Nd Concentration Data over last 25,000 Years Xie, R.C.; Marcantonio, F. Xie, R.C. Marcantonio, F. Intertropical Convergence Zone (ITCZ) earth science/paleoclimate/paleoceanography (notes,null,null,null,null,paleoceanography,null,null,C,null) earth science/paleoclimate/paleoceanography (age,null,null,calendar kiloyear before present,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (notes,null,null,null,null,paleoceanography,null,null,N,percent residual) earth science/paleoclimate/paleoceanography (87Sr/86Sr,sediment,one standard error,dimensionless,null,paleoceanography,null,thermal ionization mass spectrometry,N,with DTPA) earth science/paleoclimate/paleoceanography (208Pb/204Pb,sediment,null,dimensionless,null,paleoceanography,null,thermal ionization mass spectrometry,N,null) earth science/paleoclimate/paleoceanography (207Pb/206Pb,sediment,null,dimensionless,null,paleoceanography,null,thermal ionization mass spectrometry,N,null) earth science/paleoclimate/paleoceanography (208Pb/206Pb,sediment,null,dimensionless,null,paleoceanography,null,thermal ionization mass spectrometry,N,null) earth science/paleoclimate/paleoceanography (207Pb/204Pb,sediment,null,dimensionless,null,paleoceanography,null,thermal ionization mass spectrometry,N,null) earth science/paleoclimate/paleoceanography (87Sr/86Sr,sediment,null,dimensionless,null,paleoceanography,null,thermal ionization mass spectrometry,N,without DTPA) earth science/paleoclimate/paleoceanography (neodymium,sediment,null,milligram per kilogram,null,paleoceanography,null,inductively-coupled plasma atomic emission spectroscopy,N,bulk Nd) earth science/paleoclimate/paleoceanography (neodymium,sediment,null,percent,null,paleoceanography,null,null,N,in crust) earth science/paleoclimate/paleoceanography (87Sr/86Sr,sediment,one standard error,dimensionless,null,paleoceanography,null,thermal ionization mass spectrometry,N,without DTPA) earth science/paleoclimate/paleoceanography (epsilon neodymium,sediment,null,epsilon unit,null,paleoceanography,null,thermal ionization mass spectrometry,N,null) earth science/paleoclimate/paleoceanography (206Pb/204Pb,sediment,null,dimensionless,null,paleoceanography,null,thermal ionization mass spectrometry,N,null) earth science/paleoclimate/paleoceanography (87Sr/86Sr,sediment,null,dimensionless,null,paleoceanography,null,thermal ionization mass spectrometry,N,with DTPA) earth science/paleoclimate/paleocean (ODP 850>LATITUDE 1.2972>LONGITUDE -110.5214) (ODP 849>LATITUDE .18>LONGITUDE -110.52) (ODP 851>LATITUDE 2.77>LONGITUDE -110.57) (ODP 852>LATITUDE 5.292633>LONGITUDE -110.076067) (ODP 848>LATITUDE -2.994083>LONGITUDE -110.479983) (ODP 853>LATITUDE 7.210917>LONGITUDE -109.7513) The provenance of eolian dust supplied to deep-sea sediments has the potential to offer insights into changes in past atmospheric circulation. Specifically, measuring temporal changes in dust provenance can shed light on changes in the mean position of the Intertropical Convergence Zone (ITCZ), a region acting as a barrier separating wind-blown material derived from northern versus southern hemisphere sources. Here we have analyzed Nd, Sr, and Pb isotope ratios in the operationally-defined detrital component extracted from deep-sea sediments in the eastern equatorial Pacific (EEP) along a meridional transect at 110°W from 3°S to 7°N (ODP Leg 138, sites 848–853). Sr isotope results show that barite Sr has a significant influence on 87Sr/86Sr isotope ratios of samples in the upwelling zone of the EEP. However, sites located >3° or more away from the equator (sites 852 and 853) are believed to not be affected by barite Sr and provide useful detrital Sr signals. 208Pb/206Pb and 207Pb/206Pb ratios in all cores fall into the Pb-isotope space of five potential dust sources (Asia, North and Central/South America, Sahara, and Australia), with no distinct isotopic fingerprinting of the dominant source(s). εNd values were most valuable for discerning detrital source provenance, and their values at all sites, ranging from −5.46 to −3.25, were more unradiogenic for sediments deposited during the last glacial than for those deposited during the Holocene. There are distinct latitudinal trends in the εNd values, with more radiogenic values further south and less radiogenic values further north, excluding site 848. This distinction holds true for both Holocene and last glacial periods. For the most southerly site, 848, we invoke, for the first time, a distinct southern hemisphere Australian source as being responsible for the unradiogenic Nd isotope ratios. Both average last glacial and Holocene εNd values show similar sharp gradients along the transect between 5.29°N and 2.77°N, suggesting little movement of the glacial ITCZ in the EEP. However, during the deglacial, this gradient is stronger and shifted further north between 5.29°N and 7.21°N, suggesting a more northerly, possibly stronger, deglacial ITCZ. STUDY NOTES: The provenance of eolian dust supplied to deep-sea sediments has the potential to offer insights into changes in past atmospheric circulation. Specifically, measuring temporal changes in dust provenance can shed light on changes in the mean position of the Intertropical Convergence Zone (ITCZ), a region acting as a barrier separating wind-blown material derived from northern versus southern hemisphere sources. Here we have analyzed Nd, Sr, and Pb isotope ratios in the operationally-defined detrital component extracted from deep-sea sediments in the eastern equatorial Pacific (EEP) along a meridional transect at 110°W from 3°S to 7°N (ODP Leg 138, sites 848 – 853). Sr isotope results show that barite Sr has a significant influence on 87Sr/86Sr isotope ratios of samples in the upwelling zone of the EEP. However, sites located >3° or more away from the equator (sites 852 and 853) are believed to not be affected by barite Sr and provide useful detrital Sr signals. 208Pb/206Pb and 207Pb/206Pb ratios in all cores fall into the Pb-isotope space of five potential dust sources (Asia, North and Central/South America, Sahara, and Australia), with no distinct isotopic fingerprinting of the dominant source(s). εNd values were most valuable for discerning detrital source provenance, and their values at all sites, ranging from -5.46 to -3.25, were more unradiogenic for sediments deposited during the last glacial than for those deposited during the Holocene. There are distinct latitudinal trends in the εNd values, with more radiogenic values further south and less radiogenic values further north, excluding site 848. This distinction hold s true for both Holocene and last glacial periods. For the most southerly site, 848, we invoke, for the first time, a distinct southern hemisphere Australian source as being responsible for the unradiogenic Nd isotope ratios. Both average last glacial and Holocene εNd values show similar sharp gradients along the transect between 5.29°N and 2.77°N, suggesting little movement of the glacial ITCZ in the EEP. However, during the deglacial, this gradient is stronger and shifted further north between 5.29°N to 7.21°N, suggesting a more northerly, possibly stronger, deglacial ITCZ. There are 6 cores in total in our study. Provided keywords: Radiogenic isotopes, Intertropical Convergence Zone, dust provenance NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Xie, R.C. Investigator : Marcantonio, F. 2014-10-27 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/17371 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/xie2012-epsl/xie2012-epsl-odp848.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/xie2012-epsl/xie2012-epsl-odp849.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/xie2012-epsl/xie2012-epsl-odp853.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/xie2012-epsl/xie2012-epsl-odp851.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/xie2012-epsl/xie2012-epsl-odp850.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/xie2012-epsl/xie2012-epsl-odp852.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/xie2012-epsl/xie2012-epsl-odp848.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/xie2012-epsl/xie2012-epsl-odp849.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/xie2012-epsl/xie2012-epsl-odp853.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/xie2012-epsl/xie2012-epsl-odp851.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/xie2012-epsl/xie2012-epsl-odp850.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/xie2012-epsl/xie2012-epsl-odp852.txt English https://www.ncdc.noaa.gov/paleo/study/17371 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/xie2012-epsl/xie2012-epsl-odp848.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/xie2012-epsl/xie2012-epsl-odp849.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/xie2012-epsl/xie2012-epsl-odp853.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/xie2012-epsl/xie2012-epsl-odp851.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/xie2012-epsl/xie2012-epsl-odp850.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/xie2012-epsl/xie2012-epsl-odp852.txt Xie, R.C. and F. Marcantonio2012Deglacial dust provenance changes in the Eastern Equatorial Pacific and implications for ITCZ movement during Last GlaciationEarth and Planetary Science Letters317386-39510.1016/j.epsl.2011.11.014 START YEAR: 25000 cal yr BP * END YEAR: 900 cal yr BP -110.57 -2.994083 -109.7513 7.210917