# Southern Ocean ODP745 Miocene-Pleistocene d15N Data #----------------------------------------------------------------------- # World Data Center for Paleoclimatology, Boulder # and # NOAA Paleoclimatology Program #----------------------------------------------------------------------- # NOTE: Please cite original reference when using these data, # plus the Online Resource and date accessed. # # # Online_Resource: http://hurricane.ncdc.noaa.gov/pls/paleox/f?p=519:1:::::P1_STUDY_ID:13671 # # Original_Source_URL: ftp://ftp.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/billups2013/billups2013.txt # # Description/Documentation lines begin with # # Data lines have no # # # Archive: Paleoceanography #-------------------- # Contribution_Date # Date: 2013-01-03 #-------------------- # Title # Study_Name: Southern Ocean ODP745 Miocene-Pleistocene d15N Data #-------------------- # Investigators # Investigators: Billups, K.; Aufdenkampe, A.; Hays, R. #-------------------- # Description_and_Notes # # Bulk sediment d15N values from ODP Site 745 in the Antarctic Zone of the Southern Ocean # for 6.5 - 1.4 ma, to assess potential changes in nitrate utilization and export production # from the late Miocene through early Pleistocene. The temporal resolution is about 30-75 kyr. # Approximately 1 g of sediment was freeze dried, ground with a mortar and pestle into a fine powder, # and homogenized. About 90-100 mg of the thus prepared bulk sediment was weighed out into tin cups. # Approximately 10 mg of powdered tin was added to each sample to aid with combustion given the low # organic matter concentrations. Samples were then analyzed at the Stroud Water Research Center # on a Thermo-Finnigan DeltaPlus XP Isotope Ratio Mass Spectrometer (IRMS) with Conflo III # interfaced in continuous flow mode to a Costech 4010 CHNS-O Elemental Analyzer (EA). # #-------------------- # Publication # Authors: Katharina Billups, Anthony Aufdenkampe, Rebecca Hays # Published_Date_or_YEAR: 2013-01-01 # Published_Title: Late Miocene through early Pleistocene nutrient utilization and export production in the Antarctic Zone of the Southern Ocean # Journal_Name: Global and Planetary Change # Volume: 100 # Issue: # Pages: 353-361 # DOI: 10.1016/j.gloplacha.2012.11.014 # Abstract: We use bulk sediment d15N values and opal and carbon mass accumulation rates (MAR) to reconstruct nutrient utilization and export productivity at Ocean Drilling Program Site 745 (Antarctic Zone of the Southern Ocean) spanning the late Miocene through early Pleistocene (~6.5-1.4 Ma). We investigate whether early Pliocene climatic warmth and subsequent cooling can be related to changes in high latitude productivity. Results indicate that d15N values increase to above late Holocene levels from the late Miocene through the late Pliocene (6.5 to 2 Ma). Opal and carbon MARs are low during the early Pliocene. Relatively high d15N together with low export production is consistent with a more southerly position of the Polar Frontal Zone (PFZ) allowing the expansion of nitrate depleted, low nutrient upper waters south toward Site 745. The interpretation is supported by a relatively small d15N gradient between Site 745 and a site in the Subantarctic Zone of the Southern Ocean (Site 1090). There are no unique changes in the Site 745 d15N values or export productivity at 2.7 Ma. During the late Pliocene to early Pleistocene climate transition (between ~2.1 and at 1.7 Ma), d15N values display large variations approaching those observed during the last glacial to interglacial transition in this latitude band. Opal and carbon MARs also show large fluctuations, but in the opposite sense with maxima corresponding to minima in the d15N record and vice versa. The pattern of high d15N values associated with low export production may reflect changes in nutrient utilization in response to changes in water column stratification once the PFZ has moved north of the location of Site 745. Our results provide a mechanism for enhancing early Pliocene CO2 concentrations via reduced uptake of CO2 due to low productivity in the Southern Ocean. Once the PFZ has moved north, the region may have become sensitive to changes in water column stratification, potentially contributing to fluctuations in CO2. # #--------------------- # Funding_Agency # Funding_Agency_Name: American Chemical Society (ACS) Petroleum Research Fund # Grant: PRF # 49945-ND2 #-------------------- # Site_Information # Site_Name: ODP745 # Location: Ocean>Southern Ocean # Country: # Northernmost_Latitude: -59.5952 # Southernmost_Latitude: -59.5952 # Easternmost_Longitude: 85.86 # Westernmost_Longitude: 85.86 # Elevation: -4082 m #------------------ # Data_Collection # Core_Name: ODP745-2013d15n # First_Year: 6490800 # Last_Year: 1406000 # Time_Unit: Cal Year BP # Core_Length: 143 m # Notes: #------------------ # Chronology # # Ages are based on the paleomagnetic reversal pattern shown in Ehrman et al. (1991) updated to the Berggren et al. (1995) time scale # # Table 1 # Summary of age control points. # # Chron MBSF(m) B85(myr)a* B95(myr)b* # C1n 0-42.3 0-0.73 0-0.78 # C1r.1n 50.64-54.2 0.91-0.98 0.99-1.07 # C2n 91.6-92.3 1.66-1.88 1.77-1.95 # C2An.1n 112.3-123.5 2.47-2.92 2.58-3.04 # C2An.2n 125.5-126.8 2.99-3.08 3.11-3.22 # C2An.3n 128.3-133.2 3.18-3.4 3.33-3.58 # C3n.1n 142.3-145.8 3.88-3.97 4.18-4.29 # C3n.2n 150.0-155.5 4.10-4.24 4.48-4.62 # C3n.3n 161.3-163.5 4.40-4.47 4.80-4.89 # C3n.4n ? 4.57-4.77 4.98-5.22 # C3An.1n 186.2-196.1 5.35-5.53 5.89-6.15 # C3An.2n 206.1-214.2 5.68-5.98 6.30-6.58 # # a* Berggren et al. (1985). # b* Berggren et al. (1995). # #------------------ # Variables # # End Description/Documentation (lines begin with #) # Data lines follow (have no #) # Data line variables format: Variables list, one per line, shortname-tab-longname-tab-longname components (9 components: material, error, units, anomaly, period, archive, detail, method, C or N for Character or Numeric data) # Data line format: tab-delimited text, variable short name as header ## depth_m Depth (m), , , m, , , , , N ## age_calmaBP Age (calendar Million years BP), , ,cal ma BP, , , , ,N ## d15N delta N15 ave, , ,per mil, , , , , N ## d15N1 delta N15 replicate 1, , , per mil, , , , , N ## d15N2 delta N15 replicate 2, , , per mil, , , , , N ## Notes Core-Section-Interval, , , , , , , , C #----------------- # Data: # depth_m age_calmaBP d15N d15N1 d15N1 Notes Notes Notes 72 1.406 3.7862 9H 1 50-54 73.5 1.4375 4.3494 9H 2 50-54 75 1.469 2.1448 2.4164 1.8733 9H 3 50-54 76.5 1.5005 4.4031 9H 4 50-54 78 1.532 4.068 9H 5 50-54 79.5 1.5635 4.0442 9H 6 50-54 81 1.595 3.9605 4.2287 3.6924 9H 7 50-54 81.5 1.6055 4.8331 10H 1 50-54 83 1.637 3.8941 10H 2 50-54 84.5 1.6685 5.3755 5.1006 5.6503 10H 3 50-54 86 1.7 5.7608 10H 4 50-54 87.5 1.7315 4.51 10H 5 50-54 89 1.763 5.3763 10H 6 50-54 90.5 1.7945 4.5566 10H 7 50-54 91 1.805 4.9099 11H 1 50-54 92.5 1.8365 2.9025 11H 2 50-54 94 1.8834 2.4272 11H 3 50-54 95.5 1.9381 0.9308 0.883 0.9786 11H 4 50-54 97 1.9937 5.18 11H 5 50-54 98.5 2.0504 5.4376 11H 6 50-54 100.5 2.1274 5.2584 4.9179 5.5989 12H 1 50-54 102 2.1862 5.3968 12H 2 50-54 103.5 2.2459 4.3993 12H 3 50-54 105 2.3065 5.0581 12H 4 50-54 106.5 2.3678 4.8423 12H 5 50-54 108 2.4299 4.8043 12H 6 50-54 109.5 2.4927 4.2084 12H 7 50-54 109.99 2.5134 4.2161 13H 1 49-53 111.5 2.5776 4.2143 4.1159 4.3128 13H 2 50-54 113 2.6419 5.0068 13H 3 50-54 114.5 2.7069 4.7008 13H 4 50-54 116 2.7724 5.2664 13H 5 50-54 117.5 2.8385 4.653 13H 6 50-54 119 2.9051 4.9145 13H 7 50-54 119.5 2.9273 4.5017 14H 1 49.5-53.5 121 2.9945 3.9748 14H 2 50-54 122.5 3.062 4.947 14H 3 50-54 124 3.1299 4.5684 14H 4 50-54 125.5 3.1982 4.2742 14H 5 50-54 127 3.2667 4.7497 4.1205 5.3789 14H 6 50-54 128.5 3.3355 4.6544 14H 7 50-54 129 3.3585 4.657 15H 1 50-54 130.5 3.4276 5.0102 15H 2 50-54 132 3.4968 5.1591 15H 3 50-54 133.5 3.5662 4.2818 4.2809 4.2827 15H 4 50-54 135 3.6357 4.969 15H 5 50-54 136.5 3.7052 4.7866 15H 6 50-54 139.5 3.8443 4.5126 17H 1 50-54 141 3.9138 5.2017 5.0119 5.3914 17H 2 50-54 142.5 3.9832 4.6754 17H 3 50-54 144 4.0524 4.4554 4.4945 4.4162 17H 4 50-54 145.5 4.1215 4.3112 17H 5 50-54 147 4.1904 4.1176 17H 6 50-54 148.49 4.2587 4.2979 17H 7 49-53 148.99 4.2815 4.0348 18H 1 48.5-52.5 150.5 4.3502 4.6833 18H 2 50-54 152 4.4182 4.6546 18H 3 50-54 153.5 4.4858 6.6677 18H 4 50-54 154.98 4.5521 3.9634 18H 5 48.0-52 156.5 4.6198 3.1496 3.0379 3.2613 18H 6 50-54 158 4.6861 3.7838 18H 7 50-54 158.5 4.7081 3.5814 3.9503 3.2125 19H 1 50-54 160 4.7737 3.8652 19H 2 50-54 161.5 4.8388 3.7018 3.7944 3.6091 19H 3 50-54 163.01 4.9037 4.2409 19H 4 50-54 164.51 4.9675 3.6099 19H 5 50-54 166.01 5.0306 4.355 19H 6 50-54 167.54 5.0943 3.971 19H 7 52-56 167.99 5.1129 3.7106 20H 1 49-50 169.5 5.1748 4.63 20H 2 50-54 171 5.2355 3.9468 20H 3 50-54 172.51 5.2957 3.2267 20H 4 50-54 174.01 5.3547 3.9345 20H 5 50-54 175.54 5.4139 4.5213 4.8011 4.2416 20H 6 50-54 177.04 5.471 4.3812 20H 7 50-54 177.5 5.4883 3.8135 21H 1 50-54 179 5.5441 4.7731 4.5659 4.9803 21H 2 50-54 180.5 5.5989 3.7021 21H 3 50-54 182 5.6526 3.69 21H 4 50-54 183.5 5.7053 3.5072 21H 5 50-54 185 5.7568 3.2217 21H 6 50-54 186.5 5.8071 3.7238 21H 7 50-54 187 5.8236 4.7541 22H 1 50-54 188.5 5.8723 3.2356 22H 2 50-54 190 5.9197 3.871 22H 3 50-54 191.5 5.9659 3.5504 22H 4 50-54 193 6.0107 3.7566 3.7575 3.7557 22H 5 50-54 194.5 6.0541 3.3814 22H 6 50-54 196.51 6.1101 3.6228 23H 1 51-54 198 6.1499 3.298 23H 2 50-54 199.5 6.1885 3.899 23H 3 50-54 201 6.2255 3.8918 4.0522 3.7314 23H 4 50-54 202.5 6.261 3.1733 23H 5 50-54 204 6.2949 2.8863 23H 6 50-54 205.5 6.3272 3.9185 23H 7 50-54 206 6.3375 2.1168 24H 1 50-54 207.5 6.3675 3.0867 24H 2 50-54 209 6.3958 3.5585 24H 3 50-54 210.5 6.4223 3.8386 24H 4 50-54 212 6.447 2.497 2.2118 2.7823 24H 5 50-54 213.5 6.4699 3.9018 24H 6 50-54 215 6.4908 3.6939 24H 7 50-54