# Age model, biogenic opal contents and sedimentary U/Th for the last 150 ka at sites J1002 and J1007, Chilean Margin #----------------------------------------------------------------------- # World Data Service for Paleoclimatology, Boulder # and # NOAA Paleoclimatology Program #----------------------------------------------------------------------- # Template Version 4.0 # Encoding: UTF-8 # NOTE: Please cite original publication, NOAA Landing Page URL, dataset and publication DOIs (where available), and date accessed when using downloaded data. # If there is no publication information, please cite investigator, study title, NOAA Landing Page URL, and date accessed. # # Description/Documentation lines begin with '#' followed by a space # Data lines have no '#' # # NOAA_Landing_Page: https://www.ncei.noaa.gov/access/paleo-search/study/36494 # Landing_Page_Description: NOAA Landing Page of this file's parent study, which includes all study metadata. # # Study_Level_JSON_Metadata: https://www.ncei.noaa.gov/pub/data/metadata/published/paleo/json/noaa-ocean-36494.json # Study_Level_JSON_Description: JSON metadata of this data file's parent study, which includes all study metadata. # # Data_Type: Paleoceanography # # Dataset_DOI: 10.25921/4kpp-5998 # # Science_Keywords: Other Reconstruction #--------------------------------------- # Resource_Links # # Data_Download_Resource: https://www.ncei.noaa.gov/pub/data/paleo/contributions_by_author/li2022/li2022-expedition379t_j1007.txt # Data_Download_Description: NOAA Template File; J1007 G/B Data # #--------------------------------------- # Contribution_Date # Date: 2022-06-03 #--------------------------------------- # File_Last_Modified_Date # Date: 2025-05-28 #--------------------------------------- # Title # Study_Name: Age model, biogenic opal contents and sedimentary U/Th for the last 150 ka at sites J1002 and J1007, Chilean Margin #--------------------------------------- # Investigators # Investigators: Li, Chen; Clementi, Vincent; Bova, Samantha; Rosenthal, Yair; Childress, Laurel ; Wright, James; Jian, Zhimin #--------------------------------------- # Description_Notes_and_Keywords # Description: #--------------------------------------- # Publication # Authors: Li, C.; Clementi, V.J.; Bova, S.C.; Rosenthal, Y.; Childress, L.B.; Wright, J.D.; Jian, Z.; Expedition 379T Scientists # Published_Date_or_Year: 2022-09-01 # Published_Title: The sediment green-blue color ratio as a proxy for biogenic silica productivity along the Chilean Margin # Journal_Name: Geochemistry, Geophysics, Geosystems # Volume: 23 # Edition: # Issue: 9 # Pages: # Report_Number: e2022GC010350 # DOI: 10.1029/2022GC010350 # Online_Resource: # Full_Citation: # Abstract: Sediment cores recently collected from the Chilean Margin during D/V JOIDES Resolution Expedition 379T (JR100) document variability in shipboard-generated records of the green/blue (G/B) ratio. These changes show a strong coherence with benthic foraminiferal d 18O, Antarctic ice core records, and sediment lithology (e.g., higher diatom abundances in greener sediment intervals), suggesting a climate-related control on the G/B. Here, we test the utility of G/B as a proxy for diatom productivity at Sites J1002 and J1007 by calibrating G/B to measured biogenic opal. Strong exponential correlations between measured opal% and the G/B were found at both sites. We use the empirical regressions to generate high-resolution records of opal contents (opal%) on the Chilean Margin. Higher productivity tends to result in more reducing sedimentary conditions. Redox-sensitive sedimentary U/Th generally co-varies with the reconstructed opal% at both sites, supporting the association between sediment color, sedimentary U/Th, and productivity. Lastly, we calculated opal mass accumulation rate (MAR) at Site J1007 over the last ~150,000 years. The G/B-derived opal MAR record from Site J1007 largely tracks existing records derived from traditional wet-alkaline digestion from the south and eastern equatorial Pacific (EEP) Ocean, with a common opal flux peak at ~50 ka suggesting that increased diatom productivity in the EEP was likely driven by enhanced nutrient supply from the Southern Ocean rather than dust inputs as previously suggested. Collectively, our results identify the G/B ratio as a useful tool with the potential to generate reliable, high-resolution paleoceanographic records that circumvent the traditionally laborious methodology. #--------------------------------------- # Funding_Agency # Funding_Agency_Name: Ministry of Science and Technology of China # Grant: 2018YFE0202401 #--------------------------------------- # Funding_Agency # Funding_Agency_Name: US National Science Foundation # Grant: OCE-1756241 #--------------------------------------- # Funding_Agency # Funding_Agency_Name: Department of Energy's National Energy Technology Laboratory (NETL) # Grant: Methane Hydrates Fellowship Program #--------------------------------------- # Site_Information # Site_Name: J1007 # Location: Eastern Pacific Ocean # Northernmost_Latitude: -36.5423 # Southernmost_Latitude: -36.5425 # Easternmost_Longitude: -73.6663 # Westernmost_Longitude: -73.6665 # Elevation_m: 787.11 #--------------------------------------- # Data_Collection # Collection_Name: Expedition _379T_J1007 # First_Year: 169320 # Last_Year: 400 # Time_Unit: calendar year before present # Core_Length_m: 119.02 # Parameter_Keywords: age control, physical properties # Notes: #--------------------------------------- # Chronology_Information # Chronology: Radiocarbon # Chronology_Download_Resource: https://www.ncei.noaa.gov/pub/data/paleo/templates/noaa-wds-paleo-14c-terms.csv # Chronology_Download_Description: Radiocarbon terms and definitions. # Chronology_Notes: J1007 Chronology Table # Rejection_Rationale: # Reservoir_Method: # Calibration_Method: # Age_Model_Method: # Missing_Values: # Chronology_Table: # lab_code depth_end_m depth_start_m material_dated age_14C_BP1950 age_14C_1s_yr date_type age_calib_BP1950 age_calib_pos2s_BP1950 age_calib_neg2s_BP1950 calib_curve # UCIAMS-240402 3.41 3.43 G. bulloides 12230 35 14C AMS 12172 12292 12103 IntCal20 # UCIAMS-240398 4.797 4.817 G. bulloides 14430 140 14C AMS 15659 16111 15314 IntCal20 # UCIAMS-240401 6.409 6.429 G. bulloides 16150 70 14C AMS 17547 17679 17273 IntCal20 # UCIAMS-240399 12.79 12.81 G. bulloides 21570 130 14C AMS 23915 24103 23703 IntCal20 # UCIAMS-240400 15.99 16.01 G. bulloides 24970 170 14C AMS 27181 27817 26859 IntCal20 # UCIAMS-240405 17.583 17.623 G. bulloides 27820 190 14C AMS 29784 30248 29274 IntCal20 # UCIAMS-240403 22.765 22.865 G. bulloides 34080 480 14C AMS 37142 38308 35598 IntCal20 #--------------------------------------- # Variables # PaST_Thesaurus_Download_Resource: https://www.ncei.noaa.gov/access/paleo-search/skos/past-thesaurus.rdf # PaST_Thesaurus_Download_Description: Paleoenvironmental Standard Terms (PaST) Thesaurus terms, definitions, and relationships in SKOS format. # # Data variables follow that are preceded by "##" in columns one and two. # Variables list, one per line, shortname-tab-var components: what, material, error, units, seasonality, data type, detail, method, C or N for Character or Numeric data) # ## Depth depth,,,meter,,Paleoceanography,,,N, ## Age age,,,calendar kiloyear before present,,Paleoceanography,,,N, ## G/B green intensity/blue intensity,sediment,,dimensionless,,Paleoceanography,,,N,ratio of sedimentary green to blue ratio ## Corg% organic carbon,sediment,,percent,,Paleoceanography,,,N, ## Opal% biogenic silica,sediment,,percent,,Paleoceanography,,,N, ## Notes notes,,,,,Paleoceanography,,,C, ## Site sample identification,,,,,Paleoceanography,,,C, #------------------------ # Data: # Data lines follow (have no #) # Data line format - tab-delimited text, variable short name as header # Missing_Values: -999 Depth Age G/B Corg% Opal% Notes Site 0.1 0.4 1.182 2.38 -999 -999 J1007 0.11 0.44 1.185 2.02 3.54 -999 J1007 4.797 17.25 1.141 0.67 -999 -999 J1007 6.409 19.37 1.169 0.76 2.8 -999 J1007 8.009 21.04 1.088 0.75 -999 -999 J1007 9.609 22.64 1.116 0.8 1.92 -999 J1007 11.209 24.25 1.108 0.87 1.89 -999 J1007 12.803 25.89 1.079 0.74 2.63 -999 J1007 14.393 27.61 1.126 0.92 4.34 -999 J1007 16.003 29.26 1.133 1.11 -999 -999 J1007 17.61 31.67 1.17 1.08 -999 -999 J1007 19.21 33.73 1.163 1.06 -999 -999 J1007 20.83 35.89 1.187 0.92 -999 -999 J1007 22.375 38.11 1.187 0.99 3.8 -999 J1007 24.006 39.65 1.171 0.97 -999 -999 J1007 25.606 40.64 1.162 1.19 3.81 -999 J1007 27.236 41.65 1.183 1.03 3.91 -999 J1007 28.808 42.76 1.161 0.9 -999 -999 J1007 30.408 43.94 1.179 1 -999 -999 J1007 32.008 44.87 1.192 1.09 -999 -999 J1007 33.599 45.72 1.189 1.13 4.9 -999 J1007 35.199 46.49 1.166 0.71 -999 -999 J1007 36.799 47.26 1.172 0.73 -999 -999 J1007 38.399 48.11 1.141 0.76 -999 -999 J1007 40.006 48.99 1.128 0.82 -999 -999 J1007 41.606 49.7 1.137 0.92 3.41 -999 J1007 43.206 50.38 1.186 -999 4.34 -999 J1007 44.801 51 1.178 1 -999 -999 J1007 46.401 51.61 1.165 1.24 -999 -999 J1007 48.001 52.29 1.238 1.92 5.34 -999 J1007 49.605 53.11 1.177 1.63 5.35 -999 J1007 50.405 53.73 1.196 1.3 -999 -999 J1007 51.205 54.45 1.216 2.19 -999 -999 J1007 55.205 57.83 1.203 0.81 -999 -999 J1007 56.001 58.53 1.236 0.75 -999 -999 J1007 56.806 59.26 1.168 0.64 -999 -999 J1007 57.601 60.23 1.172 0.73 -999 -999 J1007 59.201 63.06 1.126 0.6 -999 -999 J1007 60.801 66.01 1.098 0.64 2.4 -999 J1007 62.402 68.95 1.162 0.81 -999 -999 J1007 64.002 71.9 1.187 0.73 -999 -999 J1007 64.802 73.42 1.169 0.73 -999 -999 J1007 65.602 75.21 1.151 0.67 -999 -999 J1007 67.197 79.48 1.121 0.71 2.87 -999 J1007 68.797 83.87 1.093 0.6 -999 -999 J1007 70.298 87.32 1.185 0.66 2.83 -999 J1007 72.003 91.02 1.129 0.69 2.77 -999 J1007 73.603 94.48 1.167 0.7 -999 -999 J1007 74.303 96 1.168 0.66 -999 -999 J1007 74.803 97.08 1.116 0.66 -999 -999 J1007 75.203 97.94 1.135 0.7 3.53 -999 J1007 75.703 99.03 1.152 0.68 -999 -999 J1007 76.204 100.11 1.172 0.68 -999 -999 J1007 76.799 101.41 1.18 0.71 -999 -999 J1007 78.399 105.5 1.147 0.71 -999 -999 J1007 79.996 111.95 1.188 0.84 -999 -999 J1007 80.501 114.12 1.265 0.94 -999 -999 J1007 81.001 116.28 1.238 0.93 -999 -999 J1007 81.596 118.31 1.186 0.8 3.65 -999 J1007 83.2 121.71 1.189 0.8 -999 -999 J1007 84.8 124.26 1.186 0.7 -999 -999 J1007 86.4 126.87 1.126 0.58 -999 -999 J1007 87.86 128.84 1.171 0.68 -999 -999 J1007 89.602 130.97 1.146 0.73 2.85 -999 J1007 92.202 134.08 1.178 0.97 -999 -999 J1007 95.408 137.96 1.287 1.49 -999 -999 J1007 97.008 139.99 1.214 0.64 -999 -999 J1007 98.609 142.12 1.201 0.67 -999 -999 J1007 99.979 143.95 1.224 0.93 3.74 -999 J1007 102.419 147.2 1.111 0.78 -999 -999 J1007 103.413 148.53 1.136 0.6 -999 -999 J1007 105.013 150.66 1.157 0.59 -999 -999 J1007 106.613 152.79 1.124 0.53 -999 -999 J1007 108.213 154.93 1.118 0.58 -999 -999 J1007 111.454 159.25 1.084 0.61 -999 -999 J1007 113.019 161.33 1.128 0.59 -999 -999 J1007 114.615 163.46 1.217 1.15 -999 -999 J1007 116.215 165.6 1.194 0.83 -999 -999 J1007 117.815 167.73 1.234 0.9 -999 -999 J1007 119.005 169.32 1.181 0.74 -999 -999 J1007 1.605 6.44 1.208 1.72 2.2 Data_points_with_underestimated_opal_contents. J1007 1.615 6.48 1.22 1.86 2.55 Data_points_with_underestimated_opal_contents. J1007 3.205 12.87 1.187 1.16 1.99 Data_points_with_underestimated_opal_contents. J1007 52.005 55.16 1.243 1.27 3.03 Data_points_with_underestimated_opal_contents. J1007 52.805 55.84 1.25 1.43 3.97 Data_points_with_underestimated_opal_contents. J1007 53.605 56.49 1.253 1.25 2.53 Data_points_with_underestimated_opal_contents. J1007 54.405 57.15 1.215 0.9 1.98 Data_points_with_underestimated_opal_contents. J1007 93.838 136.04 1.207 0.89 2.74 Data_points_with_underestimated_opal_contents. J1007