# Equatorial Pacific Ocean Alkenone and Radiogenic Isotope Data covering the last 40,000 years #----------------------------------------------------------------------- # World Data Service for Paleoclimatology, Boulder # and # NOAA Paleoclimatology Program #----------------------------------------------------------------------- # Template Version 3.0 # Encoding: UTF-8 # 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. # # Description/Documentation lines begin with # # Data lines have no # # # Online_Resource: https://www.ncdc.noaa.gov/paleo/study/25630 # Description: NOAA Landing Page # Online_Resource: http://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/anderson2018/anderson2018-mc19.txt # Description: NOAA location of the template # # Data_Type: Paleoceanography # # Dataset_DOI: # # Parameter_Keywords: biomarkers, radiogenic isotope #--------------------------------------- # Contribution_Date # Date: 2018-11-27 #--------------------------------------- # File_Last_Modified_Date # Date: 2018-11-27 #--------------------------------------- # Title # Study_Name: Equatorial Pacific Ocean Alkenone and Radiogenic Isotope Data covering the last 40,000 years #--------------------------------------- # Investigators # Investigators: Anderson, R.F.; Sachs, J.P.; Fleisher, M.Q.; Allen, K.A.; Yu, J.; Koutavas, A.; Jaccard, S.L. #--------------------------------------- # Description_Notes_and_Keywords # Description: Combination of data from previous publications and new data # Provided Keywords: Pacific Ocean, deglacial, last ice age #--------------------------------------- # Publication # Authors: Anderson R.F., J.P. Sachs, M.Q. Fleisher, K.A. Allen, J. Yu, A. Koutavas, S.L. Jaccard # Published_Date_or_Year: # Published_Title: Deep-sea oxygen depletion and ocean carbon sequestration during the last ice age # Journal_Name: Global Biogeochemical Cycles # Volume: under review # Edition: # Issue: # Pages: # Report_Number: # DOI: # Online_Resource: # Full_Citation: # Abstract: Enhanced ocean carbon storage during the Pleistocene ice ages lowered atmospheric CO2 concentrations by 80 to 100 ppm relative to interglacial levels. Leading hypotheses to explain this phenomenon invoke a greater efficiency of the ocean’s biological pump, in which case carbon storage in the deep sea would have been accompanied by a corresponding reduction in dissolved oxygen. We exploit the sensitivity of organic matter preservation in marine sediments to bottom water oxygen concentration to constrain the level of dissolved oxygen in the deep central equatorial Pacific Ocean during the last glacial period (18,000 – 28,000 years BP) to have been within the range of 20 - 50 µmol/kg, much less than modern value of ca. 168 µmol/kg. We further demonstrate that reduced oxygen levels characterized the water column below a depth of ~1000 m. Converting the ice-age oxygen level to an equivalent concentration of respiratory CO2, and extrapolating globally, we estimate that deep-sea CO2 storage during the last ice age exceeded modern values by as much as 850 PgC, sufficient to balance the loss of carbon from the atmosphere (ca. 200 PgC) and from the terrestrial biosphere (ca. 300 - 600 PgC). In addition, recognizing the enhanced preservation of organic matter in ice-age sediments of the deep Pacific Ocean helps reconcile previously unexplained inconsistencies among different geochemical proxy records used to assess past changes in biological productivity of the ocean. #--------------------------------------- # Publication # Authors: Anderson, R.F., M.Q. Fleisher, and Y. Lao # Published_Date_or_Year: 2006 # Published_Title: Glacial-Interglacial variability in the delivery of dust to the central equatorial Pacific Ocean # Journal_Name: Earth and Planetary Science Letters # Volume: 242 # Edition: # Issue: # Pages: 406-414 # Report_Number: # DOI: 10.1016/j.epsl.2005.11.061 # Online_Resource: # Full_Citation: # Abstract: Fluxes of continental mineral aerosols (dust) were greater during glacial periods than during interglacials throughout most regions of the Earth. The equatorial Pacific Ocean was a possible exception to this pattern in that previous studies have reported either greater dust fluxes during interglacials or no consistent glacial-interglacial pattern of dust flux. We have applied the 230Thnormalization technique to derive five new records of dust flux from central equatorial Pacific Ocean sediments. In contrast to previous studies, which relied on stratigraphic accumulation rates, the 230Th-normalization technique produces internally consistent results, revealing fluxes to this region of continental lithogenic material that were positively correlated with global ice volume throughout the past 300,000 yr. Maximum glacial fluxes of continental mineral aerosols exceed minimum interglacial fluxes by about a factor of 2, similar to changes found elsewhere at low and mid-latitudes. This amplitude of variability is substantially smaller than that seen in some recent models, and these observations provide a calibration point for future model development. #--------------------------------------- # Publication # Authors: Anderson, R.F., M.Q. Fleisher, Y. Lao, and G. Winckler # Published_Date_or_Year: 2008 # Published_Title: Modern CaCO3 preservation in equatorial Pacific sediments in the context of recent glacial cycles # Journal_Name: Marine Chemistry # Volume: 111 # Edition: # Issue: # Pages: 30-46 # Report_Number: # DOI: 10.1016/j.marchem.2007.11.011 # Online_Resource: # Full_Citation: # Abstract: The CaCO3 content of marine sediments in many regions of the ocean has varied systematically with climate throughout the late-Pleistocene glacial cycles. Both biological productivity and carbonate preservation have been proposed to be the master variable regulating this variability. We have evaluated the preserved flux of CaCO3 in cores from the central equatorial Pacific Ocean (~ 140°W) using the 230Th-normalization technique. Neither barite fluxes nor 10Be/230Th ratios, both geochemical proxies for export production, correlate with CaCO3 fluxes, indicating that productivity is not the principal factor controlling CaCO3 accumulation in these sediments. Preserved fluxes of CaCO3 in central equatorial Pacific sediments correlate in time with the benchmark CaCO3 record from the Cape Basin (South Atlantic Ocean), supporting the view that changes in ocean chemistry (carbonate ion concentration) have controlled the pattern of CaCO3 preservation and accumulation at these sites. Modern CaCO3 preservation in equatorial Pacific sediments has dropped to levels nearly as low as those experienced at any time in the late Pleistocene. Similar changes occurred at the end of each of the late-Pleistocene interglacial periods, from which we infer that ocean carbonate chemistry has already undergone changes that are expected to precede the transition into the next ice age. However, during the late Pleistocene, the time interval between the decrease in CaCO3 preservation and the end of the interglacial has varied substantially from one interglacial to another (from ~ 2000 to ~ 15,000 years), so the late-Holocene decrease in CaCO3 preservation cannot be used to predict the end of the Holocene interglacial period. #--------------------------------------- # Funding_Agency # Funding_Agency_Name: US National Science Foundation # Grant: #--------------------------------------- # Funding_Agency # Funding_Agency_Name: Swiss National Science Foundation # Grant: PP00P2-144811, PP00P2-172915 #--------------------------------------- # Site_Information # Site_Name: TT013-MC19 # Location: Pacific Ocean # Country: # Northernmost_Latitude: -1.8680 # Southernmost_Latitude: -1.8680 # Easternmost_Longitude: -139.7157 # Westernmost_Longitude: -139.7157 # Elevation: -4354 #--------------------------------------- # Data_Collection # Collection_Name: TT013-MC19 radiogenic Anderson2018 # First_Year: 15000 # Last_Year: 0 # Time_Unit: cal yr BP # Core_Length: # Notes: #--------------------------------------- # Chronology_Information # Chronology: #--------------------------------------- # Variables # Data variables follow that are preceded by "##" in columns one and two. # Variables list, one per line, shortname-tab-longname components (9 components: what, material, error, units, seasonality, archive, detail, method, C or N for Character or Numeric data) ## depth_cm depth,sediment,,centimeter,,Paleoceanography,,,N, ## age_BP age,sediment,,calendar kiloyear before present,,Paleoceanography,,,N,age from published age models, see metadata for publications ## 238U 238U,sediment,,disintegration per minute per gram,,Paleoceanography,,inductively-coupled plasma mass spectrometry,N,units - decays per minute per gram, a standard for sediment radiochemistry ## 238U_error 238U,sediment,one standard deviation,disintegration per minute per gram,,Paleoceanography,,inductively-coupled plasma mass spectrometry,N,units - decays per minute per gram, a standard for sediment radiochemistry ## 232Th 232Th,sediment,,disintegration per minute per gram,,Paleoceanography,,inductively-coupled plasma mass spectrometry,N,units - decays per minute per gram, a standard for sediment radiochemistry ## 232Th_error 232Th,sediment,one standard deviation,disintegration per minute per gram,,Paleoceanography,,inductively-coupled plasma mass spectrometry,N,units - decays per minute per gram, a standard for sediment radiochemistry ## 230Th 230Th,sediment,,disintegration per minute per gram,,Paleoceanography,,inductively-coupled plasma mass spectrometry,N,units - decays per minute per gram, a standard for sediment radiochemistry ## 230Th_error 230Th,sediment,one standard deviation,disintegration per minute per gram,,Paleoceanography,,inductively-coupled plasma mass spectrometry,N,units - decays per minute per gram, a standard for sediment radiochemistry ## 230Th_excess_init 230Th excess,sediment,,disintegration per minute per gram,,Paleoceanography,,,N,derived as described in text; 230Th excess initial ## 230Th_excess_init_error 230Th excess,sediment,one standard deviation,disintegration per minute per gram,,Paleoceanography,,,N,derived as described in text; 230Th excess initial ## 230Th_normalized_accum_rate 230Th,sediment,,gram per square centimeter per kiloyear,,Paleoceanography,,,N,derived as described in text; 230Th-normalized accumulation rate ## 230Th_normalized_accum_rate_error 230Th,sediment,one standard deviation,gram per square centimeter per kiloyear,,Paleoceanography,,,N,derived as described in text; 230Th-normalized accumulation rate ## barium_excess barium excess,sediment,,parts per million,,Paleoceanography,,,N,derived as described in text ## opal biogenic silica,sediment,,percent,,Paleoceanography,,spectrophotometry,N, #------------------------ # Data: # Data lines follow (have no #) # Data line format - tab-delimited text, variable short name as header # Missing_Values: NA depth_cm age_BP 238U 238U_error 232Th 232Th_error 230Th 230Th_error 230Th_excess_init 230Th_excess_init_error 230Th_normalized_accum_rate 230Th_normalized_accum_rate_error barium_excess opal 1.5 4.61 0.240 0.008 0.049 0.005 17.74 0.22 18.46 0.23 0.616 0.008 NA 9.02 3.5 5.11 0.262 0.011 0.056 0.005 17.83 0.23 18.64 0.24 0.610 0.008 NA 10.30 4.5 5.37 0.226 0.009 0.061 0.008 17.11 0.30 17.92 0.32 0.635 0.011 NA 9.45 5.5 5.62 0.276 0.011 0.047 0.005 16.51 0.21 17.34 0.22 0.656 0.008 NA 9.89 6.5 5.87 0.296 0.009 0.047 0.006 15.75 0.20 16.57 0.21 0.687 0.009 NA 9.47 7.5 6.13 0.284 0.011 0.048 0.005 15.57 0.19 16.42 0.20 0.693 0.009 NA 9.64 8.5 6.38 0.303 0.010 0.041 0.005 15.05 0.19 15.91 0.20 0.715 0.009 NA 9.27 9.5 6.63 0.313 0.009 0.040 0.007 13.68 0.20 14.49 0.21 0.785 0.011 NA 9.33 13.0 7.52 0.287 0.009 0.043 0.006 11.86 0.18 12.66 0.19 0.899 0.014 NA 8.61 15.5 8.98 0.233 0.008 0.046 0.007 9.56 0.18 10.33 0.20 1.101 0.021 NA 6.18 17.0 9.85 0.195 0.008 0.038 0.005 9.20 0.15 10.03 0.16 1.135 0.018 NA 5.98 19.0 11.02 0.227 0.008 0.060 0.006 8.73 0.15 9.59 0.16 1.186 0.020 NA 6.37 21.0 12.18 0.210 0.008 0.049 0.006 8.71 0.15 9.68 0.17 1.176 0.021 NA 5.37 23.0 13.35 0.227 0.008 0.052 0.006 8.14 0.14 9.14 0.16 1.245 0.021 NA NaN