# Southeastern Indian Ocean Mg/Ca, Ba/Ca, d18O and SST data over the last 17,000 yr BP #----------------------------------------------------------------------- # World Data Service for Paleoclimatology, Boulder # and # NOAA Paleoclimatology Program #----------------------------------------------------------------------- # 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/ # Description: NOAA Landing Page # Online_Resource: https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/by_contributor/weldeab2014/weldeab2014-gb9310-4.txt # Description: NOAA location of the template # # Archive: Paleoceanography # # Parameter_Keywords: trace metals in carbonates, oxygen isotopes #--------------------------------------- # Contribution_Date # Date: 2017-06-26 #--------------------------------------- # File_Last_Modified_Date # Date: 2017-06-26 #--------------------------------------- # Title # Study_Name: Southeastern Indian Ocean Mg/Ca, Ba/Ca, d18O and SST data over the last 17,000 yr BP #--------------------------------------- # Investigators # Investigators: Weldeab, S.; Lea, D. W.; Oberhänsli, H.; Schneider, R.R. #--------------------------------------- # Description_Notes_and_Keywords # Description: #--------------------------------------- # Publication # Authors: Weldeab, S., D.W. Lea, H. Oberhänsli, and R.R. Schneider # Published_Date_or_Year: 2014 # Published_Title: Links between southwestern tropical Indian Ocean SST and precipitation over southeastern Africa over the last 17 kyr # Journal_Name: Palaeogeography, Palaeoclimatology, Palaeoecology # Volume: 410 # Edition: # Issue: # Pages: 200-212 # Report Number: # DOI: 10.1016/j.palaeo.2014.06.001 # Online_Resource: # Full_Citation: # Abstract: Time series of Mg/Ca, Ba/Ca, and d18O analyzed in tests of surface-dwelling planktonic foraminifer Globigerinoides ruber fromtwo marine sediment cores recovered in theMozambique Channel off the Zambezi River, southwestern tropical Indian Ocean, reveal climate variability over the last 17 kyr. Analysis of samples collected from the water column of the Mozambique Channel validates thatMg/Ca in G. ruber reflects calcification temperatures at 0–30m water depth and that the surface water of the southwestern Indian Ocean is very sensitive to dissolved Ba input from adjacent rivers. Foraminiferal Ba/Ca and Mg/Ca time series are used to reconstruct hydrological and thermal changes over southeastern African and southwestern tropical oceans. The Mg/Ca-based sea surface temperature (SST) estimates indicate that the thermal evolution of the tropical southwestern Indian Ocean followed, within age model uncertainties, climate changes over Antarctica. The trend of the SST record is marked by a gradual warming from 24.7 ± 0.6 °C at 17.0± 0.2 kyr BP to 26.4± 0.3 °C at 10–11 kyr BP interrupted by two prominent coolings of ~1.5±0.2 °C and ~1 °C centered at 15±0.1 kyr BP and 13.4±0.2 kyr BP, respectively. Declining SSTs in the early Holocene reach their minimum (25 °C) at 8.7 ± 0.2 kyr BP and give way to stable thermal conditions over the Middle and Late Holocene. The Ba/Ca record indicates that the Zambezi basin experienced relatively wet conditions during the early phase of the last deglaciation, Bølling–Allerød, and the early Holocene. These wet phases coincidewith an increase of SST in theMozambique Channel. In contrast, relatively dry conditions throughout the middle and late Holocene epoch are accompanied by relatively cold Mozambique Channel surface water. These shifts likely reflect a response to meridional shifts of the austral westerlies and subtropical front. These hypothesized shifts would have modulated the advection of cold Southern Ocean water into the Mozambique Channel. Changes in SST in the Mozambique Channel, and possible resultant changes in the zonal gradient in the tropical Indian Ocean, in turn, had a strong impact on the precipitation over southeastern Africa.(BWT) between 1.8? and 19.1? and ??CO?_(3 pore water)^(2-) between 33.7±4 and -34.3±4 µmol/kg in sediment depths between 1 and 10 cm. Mg/Ca and BWT are linearly correlated with a best fit of Mg/Ca[mmol/mol]=(0.36±0.02)*BWT[°C]+2.22±0.19 (r2=0.92, p: 11*10-20, and n=39). Using total alkalinity and pH data of pore water samples from 64 Atlantic multi-corer sites, we obtained ??CO?_(3 pore water)^(2-)data from the depth habitat range of Globobulimina spp. (= 1 cm = 10 cm below sediment surface). We show that ??CO?_(3 pore water)^(2-) is significantly lower than and linearly co-varies with the ??CO?_3^(2-) of the overlying bottom water: ??CO?_(3 pore water)^(2-)=(0.67±0.05)*??CO?_(3 bottom water)^(2-)-(39.84±1.98); r2=0.75, p: 6*10-20, n=64. We found a Mg/Ca sensitivity of 0.009±0.0044 mmol/mol per µmol/kg ??CO?_(3 pore water)^(2-) and Mg/Ca temperature sensitivity of 0.32 ±0.06 mmol/mol/°C after a correction for the ??CO?_(3 pore water)^(2-) effect. This study provides a robust Mg/Ca-temperature calibration, highlights that ??CO?_(3 pore water)^(2-) is spatially and most likely temporally variable, and contradicts the notion that infaunal foraminiferal Mg/Ca is relatively immune from ??CO?_(3 )^(2-) changes in the overlying bottom water. Furthermore, comparison of down core Mg/Ca data of Cibicides pachyderma and Globobulimina spp. demonstrates that the high temperature sensitivity of Mg/Ca in Globobulimina spp. presents a more robust paleothermometer to reconstruct past changes in the thermal state of the deep ocean. #--------------------------------------- # Funding_Agency # Funding_Agency_Name: National Science Foundation # Grant: OCE 0602362 #--------------------------------------- # Funding_Agency # Funding_Agency_Name: German Research Foundation Postdoctoral Fellowship Grant # Grant: WE-2686/2-1 #--------------------------------------- # Funding_Agency # Funding_Agency_Name: UCSB start-up # Grant: 560ISW #--------------------------------------- # Site Information # Site_Name: GeoB9310-4 # Location: Indian Ocean # Country: # Northernmost_Latitude: -19.203 # Southernmost_Latitude: -19.203 # Easternmost_Longitude: 37.04694 # Westernmost_Longitude: 37.04694 # Elevation: -543 #--------------------------------------- # Data_Collection # Collection_Name: GeoB9310-4 Weldeab2014 # First_Year: 13958 # Last_Year: 420 # Time_Unit: cal yr BP # Core_Length: 6.53 # Notes: #--------------------------------------- # Chronology_Information # Chronology: # # Paste Measured Radiocarbon Ages into a table below. Ages from other sources can be included using the depth, calib.14C, and notes columns # Labcode sample identification used by 14C laboratory # depth_top Depth top of sample interval (cm) # depth_bottom Depth bottom of sample interval (cm) # mat.dated Material Dated # 14C.raw conventional radiocarbon age, years before 1950AD # 14C.raw_err radiocarbon age, standard error # datemeth Dating method # reservoir Reservoir correction # delta-R Deviation from global mean reservoir correction # delta-R_err delta-R standard error # calib.14C Calibrated age # calib.14C_2sig_lo Calibrated age, 2-sigma lower confidence bound # calib.14C_2sig_up Calibrated age, 2-sigma upper confidence bound # calib_method Calibration method # # Lab Code Core depth_cm mat.dated 14C.raw_yr BP 14C.raw_error yr datemeth reservoir detlta-R delta-R error calib.14C calib.14C-2s up calib.14C-2s lo calib_method # KIA 27749 GeoB 9310-4 3 mixed plankton forams 995 40 14C AMS Marine09 203 32 429 504 309 calib v. 6.10 # KIA 27748 GeoB 9310-4 23 G sacculifer 2005 30 14C AMS Marine09 203 32 1343 1461 1263 calib v. 6.10 # KIA 27747 GeoB 9310-4 73 G sacculifer 3495 40 14C AMS Marine09 203 32 3136 3294 2973 calib v. 6.10 # KIA 27746 GeoB 9310-4 158 G sacculifer 5665 45 14C AMS Marine09 203 32 5833 5965 5698 calib v. 6.10 # KIA 27745 GeoB 9310-4 228 G sacculifer 7615 55 14C AMS Marine09 203 32 7874 7998 7726 calib v. 6.10 # KIA 27744 GeoB 9310-4 283 G sacculifer 8540 60 14C AMS Marine09 203 32 8900 9091 8653 calib v. 6.10 # KIA 27743 GeoB 9310-4 358 G sacculifer 9430 70 14C AMS Marine09 203 32 10030 10217 9775 calib v. 6.10 # KIA 27742 GeoB 9310-4 428 G sacculifer 9940 70 14C AMS Marine09 203 32 10604 10884 10430 calib v. 6.10 # KIA 27741 GeoB 9310-4 462 G sacculifer 10050 80 14C AMS Marine09 203 32 10763 11061 10554 calib v. 6.10 # KIA 28424 GeoB 9310-4 533 G. sac+ruber+siphonifera 10520 60 14C AMS Marine09 203 32 11317 11640 11176 calib v. 6.10 # KIA 27740 GeoB 9310-4 558 G sacculifer 11460 120 14C AMS Marine09 203 32 12755 13070 12566 calib v. 6.10 # KIA 28423 GeoB 9310-4 613 mixed plankton forams 12060 70 14C AMS Marine09 203 32 13316 13458 13146 calib v. 6.10 # KIA 28422 GeoB 9310-4 653 mixed plankton forams 12490 80 14C AMS Marine09 203 32 13730 13925 13467 calib v. 6.10 # #--------------------------------------- # Variables # Data variables follow that are preceded by "##" in columns one and two. # Variables list, one per line, shortname-tab- 10 components: what, material, error, units, seasonality, archive, detail, method, C or N for Character or Numeric data,additional info ## depth_cm depth,,,cm,,,,,N, ## age_calyrBP age,,,calendars years BP,,,,,N, ## Mg/Ca-g.rub magnesium/calcium,Globigerinoides ruber,,mmol/mol,,paleoceanography,,,N, ## SST-Mg/Ca sea surface temperature,Globigerinoides ruber; magnesium/calcium,,degrees Celsius,,reconstruction,,,N, calculated using Mg/Ca (mmol/mol) = 0.38*exp[0.09*T(°C)] (Dekens et al., 2002; Anand et al., 2003) ## Ba/Ca-g.rub_corr barium/calcium,Globigerinoides ruber,,µmol/mol,,paleoceanography,corrected,,N, ## d18Og.rub delta 18O,Globigerinoides ruber,,per mil PDB,,paleoceanography,,,N, ## d18Osw delta 18O,seawater,,per mil SMOW,,reconstruction,,,N, #------------------------ # Data # Data lines follow (have no #) # Data line format - tab-delimited text, variable short name as header # Missing Value: -999 depth_cm calib age_yr BP Mg/Ca_mmol/mol SST_°C Ba/Ca_µmol/mol corrected d18O _‰, PDB G. ruber d18Osw_‰, SMOW 3 419.97 4.01 26.18 0.79 -1.97 0.29 8 636.08 3.77 25.51 0.81 -1.90 0.23 13 849.91 3.73 25.38 0.70 -1.91 0.19 18 1061.42 3.82 25.65 0.78 -1.93 0.22 23 1270.60 4.16 26.59 0.69 -1.97 0.37 28 1477.42 3.75 25.43 0.75 -2.04 0.06 33 1681.88 3.68 25.22 0.89 -2.09 -0.03 38 1883.94 4.04 26.27 0.86 -2.02 0.26 43 2083.61 3.47 24.57 0.78 -2.01 -0.08 48 2280.85 -999 -999 -999 -2.08 -999 53 2475.65 3.72 25.35 0.70 -1.89 0.19 58 2668.01 3.46 24.54 0.68 -1.92 0.00 63 2857.91 3.71 25.31 0.78 -2.13 -0.05 68 3045.34 3.82 25.65 0.67 -2.13 0.02 73 3230.29 3.78 25.54 0.68 -2.04 0.08 78 3412.76 3.70 25.28 0.71 -2.05 0.02 83 3592.72 3.67 25.19 0.66 -2.10 -0.05 88 3770.18 3.53 24.77 0.73 -2.07 -0.11 93 3945.14 3.75 25.44 0.70 -2.05 0.04 98 4117.58 3.81 25.61 0.73 -1.82 0.31 103 4287.50 3.75 25.42 0.68 -2.06 0.03 108 4454.91 3.90 25.87 0.67 -999 -999 113 4619.80 3.79 25.55 0.65 -2.17 -0.06 118 4782.17 3.71 25.31 0.69 -2.07 -0.01 123 4942.03 3.87 25.79 0.80 -2.20 -0.03 128 5099.37 3.80 25.59 0.76 -2.14 -0.02 133 5254.19 3.57 24.89 0.93 -2.11 -0.14 138 5406.51 3.81 25.63 0.75 -2.23 -0.11 143 5556.33 3.69 25.25 0.70 -2.15 -0.11 148 5703.65 3.91 25.89 0.74 -1.94 0.23 153 5848.49 3.81 25.61 0.68 -1.89 0.22 158 5990.85 3.88 25.80 0.69 -1.91 0.24 163 6130.74 3.80 25.59 0.72 -2.03 0.07 168 6268.17 3.90 25.87 0.73 -1.95 0.21 173 6403.16 3.80 25.58 0.79 -1.94 0.16 178 6535.71 4.01 26.18 0.71 -1.97 0.25 183 6665.85 3.79 25.54 0.72 -1.93 0.15 188 6793.59 3.85 25.72 0.87 -2.00 0.12 193 6918.94 3.72 25.35 0.73 -2.01 0.03 198 7041.92 3.69 25.27 0.78 -1.97 0.05 203 7162.56 3.79 25.56 0.77 -1.90 0.17 208 7280.86 3.76 25.48 1.04 -1.96 0.10 218 7510.57 3.98 26.11 0.90 -999 -999 223 7622.02 3.82 25.64 0.73 -1.96 0.12 228 7731.23 3.72 25.33 0.71 -1.95 0.06 233 7838.23 3.86 25.77 0.78 -1.93 0.17 238 7943.04 3.83 25.68 0.82 -1.89 0.19 243 8045.69 3.69 25.27 0.80 -1.87 0.12 248 8146.21 3.93 25.96 0.79 -1.82 0.31 253 8244.62 3.80 25.58 0.84 -1.87 0.17 258 8340.97 3.69 25.27 0.81 -1.91 0.05 263 8435.28 3.65 25.15 0.80 -1.92 0.01 268 8527.59 3.73 25.36 0.85 -1.80 0.16 273 8617.92 3.59 24.97 0.81 -1.80 0.07 278 8706.32 3.67 25.21 0.89 -2.02 -0.10 283 8792.81 3.57 24.89 0.79 -1.88 -0.04 288 8877.45 -999 -999 -999 -1.96 -999 293 8960.26 3.91 25.89 0.83 -1.87 0.17 298 9041.29 3.61 25.00 0.75 -1.95 -0.11 303 9120.57 3.89 25.83 0.91 -1.85 0.16 308 9198.15 3.79 25.55 0.88 -1.85 0.10 313 9274.08 3.92 25.94 0.89 -1.98 0.04 318 9348.38 4.07 26.35 0.77 -1.95 0.15 323 9421.12 3.85 25.72 0.70 -1.99 -0.03 328 9492.34 3.87 25.79 0.85 -1.92 0.05 333 9562.08 4.16 26.60 1.01 -1.84 0.30 338 9630.39 3.94 25.99 0.82 -1.98 0.02 343 9697.32 3.94 26.00 0.78 -1.72 0.27 348 9762.92 4.06 26.33 0.95 -1.55 0.51 353 9827.25 4.26 26.85 1.24 -1.78 0.38 358 9890.35 4.04 26.26 0.78 -1.77 0.26 363 9952.29 4.07 26.34 0.69 -1.84 0.20 368 10013.11 4.01 26.17 0.64 -1.77 0.22 373 10072.87 3.81 25.62 0.73 -1.66 0.21 378 10131.63 3.94 25.97 0.67 -1.51 0.43 383 10189.44 3.87 25.80 0.73 -1.82 0.08 388 10246.38 4.15 26.56 0.86 -1.78 0.27 393 10302.48 3.94 25.98 0.76 -1.82 0.10 398 10357.83 3.79 25.55 0.87 -1.53 0.30 403 10412.48 3.72 25.35 0.84 -1.52 0.25 408 10466.49 -999 -999 -999 -1.78 -999 413 10519.93 3.92 25.92 -999 -1.74 0.14 418 10572.87 3.45 24.51 0.63 -1.68 -0.10 423 10625.37 4.08 26.38 0.91 -1.55 0.42 438 10780.92 4.27 26.89 0.81 -1.36 0.70 443 10832.36 3.94 25.97 0.81 -1.65 0.21 448 10883.71 4.10 26.44 0.77 -1.62 0.33 453 10935.05 4.18 26.63 0.82 -1.65 0.34 458 10986.45 3.76 25.46 0.65 -1.74 -0.01 463 11037.99 3.97 26.08 0.65 -1.66 0.20 468 11089.74 3.87 25.80 0.67 -1.58 0.21 473 11141.79 4.08 26.37 0.78 -1.64 0.26 478 11194.21 3.91 25.89 0.67 -1.67 0.13 483 11247.08 4.06 26.33 0.63 -1.44 0.44 488 11300.48 4.52 27.51 0.72 -1.69 0.44 493 11354.50 3.71 25.32 0.59 -1.48 0.18 498 11409.22 4.00 26.14 0.70 -1.73 0.09 503 11464.72 4.45 27.34 0.89 -1.64 0.42 508 11521.09 4.10 26.44 0.69 -1.41 0.46 513 11578.42 4.01 26.18 0.86 -1.64 0.17 518 11636.79 3.93 25.97 0.74 -1.41 0.35 523 11696.29 4.15 26.57 0.82 -1.26 0.61 528 11757.02 4.37 27.14 0.64 -1.36 0.63 533 11819.05 3.98 26.09 0.67 -1.26 0.50 538 11882.50 4.21 26.73 0.52 -1.31 0.58 543 11947.45 4.28 26.92 0.92 -1.21 0.71 548 12013.99 3.72 25.35 -999 -1.22 0.36 553 12082.21 3.72 25.35 1.13 -1.40 0.17 558 12152.23 3.77 25.50 0.57 -1.28 0.32 563 12224.13 3.77 25.49 0.87 -1.24 0.35 568 12298.01 -999 -999 -999 -1.26 -999 573 12373.98 3.82 25.65 0.54 -1.06 0.54 578 12452.12 3.96 26.04 0.75 -1.27 0.40 583 12532.56 3.94 25.98 0.81 -1.26 0.39 588 12615.38 3.66 25.18 0.88 -1.27 0.20 593 12700.70 4.04 26.26 0.81 -1.28 0.40 598 12788.61 3.58 24.94 0.92 -999 -999 603 12879.23 3.55 24.84 0.84 -1.34 0.03 608 12972.66 3.78 25.51 0.73 -1.35 0.15 613 13069.02 3.82 25.65 0.84 -1.30 0.21 618 13168.40 3.55 24.83 0.78 -1.29 0.04 623 13270.93 3.71 25.33 0.78 -1.34 0.08 628 13376.71 3.62 25.05 0.78 -1.20 0.15 633 13485.86 3.76 25.47 0.86 -1.27 0.16 638 13598.49 3.96 26.04 1.15 -1.26 0.27 643 13714.72 4.02 26.22 0.83 -1.17 0.39 648 13834.66 4.11 26.46 0.99 -1.33 0.27 653 13958.43 3.83 25.67 1.01 -1.20 0.22