# 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-comp.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: GeoB9307-3/GeoB9310-4 # Location: Indian Ocean # Country: # Northernmost_Latitude: -18.5525 # Southernmost_Latitude: -19.203 # Easternmost_Longitude: 37.3688 # Westernmost_Longitude: 37.04694 # Elevation: #--------------------------------------- # Data_Collection # Collection_Name: GeoB9307-3/GeoB9310-4 Weldeab2014 # First_Year: 17300 # Last_Year: 100 # Time_Unit: cal yr BP # Core_Length: # 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 28442 GeoB9307-3 3 mixed plankton forams 930 30 14C AMS Marine09 203 32 370 460 282 calib v. 6.10 # KIA 28441 GeoB9307-3 28 mixed plankton forams 2945 45 14C AMS Marine09 203 32 2463 2658 2326 calib v. 6.10 # KIA 28440 GeoB9307-3 58 mixed plankton forams 4555 35 14C AMS Marine09 203 32 4489 4648 4353 calib v. 6.10 # KIA 28438 GeoB9307-3 98 mixed plankton forams 6290 50 14C AMS Marine09 203 32 6514 6661 6374 calib v. 6.10 # KIA 28437 GeoB9307-3 148 mixed plankton forams 8910 55 14C AMS Marine09 203 32 9381 9507 9230 calib v. 6.10 # KIA 28436 GeoB9307-3 178 mixed plankton forams 9730 60 14C AMS Marine09 203 32 10383 10525 10227 calib v. 6.10 # KIA 28435 GeoB9307-3 208 mixed plankton forams 10075 60 14C AMS Marine09 203 32 10789 11050 10585 calib v. 6.10 # KIA 28434 GeoB9307-3 248 mixed plankton forams 10470 60 14C AMS Marine09 203 32 11254 11422 11126 calib v. 6.10 # KIA 28433 GeoB9307-3 258 mixed plankton forams 10540 60 14C AMS Marine09 203 32 11347 11667 11192 calib v. 6.10 # KIA 28431 GeoB9307-3 283 mixed plankton forams 10570 60 14C AMS Marine09 203 32 11406 11701 11211 calib v. 6.10 # KIA 28430 GeoB9307-3 333 mixed plankton forams 10840 60 14C AMS Marine09 203 32 11954 12275 11657 calib v. 6.10 # KIA 28429 GeoB9307-3 378 mixed plankton forams 10920 70 14C AMS Marine09 203 32 12109 12378 11828 calib v. 6.10 # KIA 28428 GeoB9307-3 413 mixed plankton forams 11220 70 14C AMS Marine09 203 32 12530 12690 12336 calib v. 6.10 # KIA 27758 GeoB9307-3 458 mixed plankton forams 11870 80 14C AMS Marine09 203 32 13161 13326 12912 calib v. 6.10 # KIA 27757 GeoB9307-3 478 mixed plankton forams 12140 90 14C AMS Marine09 203 32 13383 13632 13190 calib v. 6.10 # KIA 27755 GeoB9307-3 508 mixed plankton forams 12680 90 14C AMS Marine09 203 32 13926 14172 13722 calib v. 6.10 # KIA 27754 GeoB9307-3 533 mixed plankton forams 13120 100 14C AMS Marine09 203 32 14652 15114 14159 calib v. 6.10 # KIA 27753 GeoB9307-3 558 mixed plankton forams 13530 100 14C AMS Marine09 203 32 15502 16306 15026 calib v. 6.10 # KIA 27752 GeoB9307-3 593 mixed plankton forams 14020 120 14C AMS Marine09 203 32 16510 16886 15842 calib v. 6.10 # KIA 27751 GeoB9307-3 633 mixed plankton forams 14450 110 14C AMS Marine09 203 32 16938 17217 16696 calib v. 6.10 # 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 ## 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, ## notes notes,,,,,,,,C, #------------------------ # Data # Data lines follow (have no #) # Data line format - tab-delimited text, variable short name as header # Missing Value: -999 age_calyrBP Mg/Ca-g.rub SST-Mg/Ca Ba/Ca-g.rub_corr d18Og.rub d18Osw notes 100 3.74 25.41 -999 -2.17 -999 Binned composite 300 -999 -999 -999 -999 -999 Binned composite 500 4.01 26.18 0.79 -1.97 0.29 Binned composite 700 3.88 25.81 0.80 -1.99 0.20 Binned composite 900 3.73 25.38 0.70 -1.91 0.19 Binned composite 1100 3.79 25.55 0.79 -2.07 0.07 Binned composite 1300 4.16 26.59 0.69 -1.97 0.37 Binned composite 1500 3.73 25.37 0.97 -2.10 -0.01 Binned composite 1700 3.68 25.22 0.89 -2.09 -0.03 Binned composite 1900 4.04 26.27 0.86 -2.02 0.26 Binned composite 2100 3.67 25.21 0.80 -1.99 0.07 Binned composite 2300 -999 -999 -999 -2.08 -999 Binned composite 2500 3.71 25.32 0.76 -1.93 0.15 Binned composite 2700 3.46 24.54 0.68 -1.92 0.00 Binned composite 2900 3.88 25.81 0.92 -2.10 0.08 Binned composite 3100 3.82 25.65 0.67 -2.13 0.02 Binned composite 3300 3.86 25.76 0.78 -2.01 0.16 Binned composite 3500 3.68 25.24 0.68 -2.07 -0.02 Binned composite 3700 3.68 25.24 0.75 -2.09 -0.04 Binned composite 3900 3.75 25.44 0.70 -2.05 0.04 Binned composite 4100 3.89 25.85 0.79 -1.92 0.26 Binned composite 4300 3.75 25.42 0.68 -2.06 0.03 Binned composite 4500 3.79 25.56 0.79 -2.05 0.00 Binned composite 4700 3.77 25.51 0.71 -2.14 -0.04 Binned composite 4900 3.87 25.79 0.80 -2.20 -0.03 Binned composite 5100 3.94 25.98 0.76 -2.13 0.07 Binned composite 5300 3.57 24.89 0.93 -2.11 -0.14 Binned composite 5500 3.83 25.69 0.83 -2.16 -0.02 Binned composite 5700 3.93 25.95 0.79 -1.98 0.21 Binned composite 5900 3.84 25.71 0.69 -1.90 0.23 Binned composite 6100 3.94 25.97 0.73 -2.04 0.15 Binned composite 6300 3.83 25.67 0.84 -1.95 0.17 Binned composite 6500 3.90 25.88 0.75 -1.95 0.21 Binned composite 6700 4.07 26.33 0.81 -2.10 0.15 Binned composite 6900 3.68 25.24 0.82 -2.05 -0.03 Binned composite 7100 3.95 26.00 0.80 -2.03 0.14 Binned composite 7300 3.79 25.56 0.93 -1.99 0.08 Binned composite 7500 3.98 26.11 0.90 -999 -999 Binned composite 7700 3.81 25.62 0.77 -1.99 0.08 Binned composite 7900 4.00 26.15 0.83 -1.97 0.21 Binned composite 8100.00 3.90 25.87 0.83 -1.91 0.20 Binned composite 8300.00 3.85 25.74 0.86 -1.90 0.17 Binned composite 8500.00 3.88 25.83 0.87 -1.91 0.16 Binned composite 8700.00 3.79 25.55 0.90 -1.96 0.03 Binned composite 8900.00 3.90 25.87 0.87 -1.94 0.12 Binned composite 9100.00 3.87 25.80 0.88 -1.89 0.11 Binned composite 9300.00 3.98 26.10 0.87 -1.89 0.16 Binned composite 9500.00 3.99 26.13 0.85 -1.87 0.17 Binned composite 9700.00 4.00 26.16 0.84 -1.83 0.19 Binned composite 9900.00 4.10 26.44 0.87 -1.82 0.24 Binned composite 10100.00 4.19 26.68 0.79 -1.78 0.30 Binned composite 10300.00 3.98 26.11 0.81 -1.75 0.20 Binned composite 10500.00 3.94 25.98 0.77 -1.71 0.21 Binned composite 10700.00 4.15 26.57 0.83 -1.58 0.42 Binned composite 10900.00 4.06 26.33 0.78 -1.69 0.23 Binned composite 11100.00 3.98 26.10 0.72 -1.53 0.32 Binned composite 11300.00 3.95 26.02 0.74 -1.35 0.46 Binned composite 11500.00 4.01 26.19 0.78 -1.36 0.48 Binned composite 11700.00 3.98 26.11 0.79 -1.24 0.54 Binned composite 11900.00 3.97 26.07 0.73 -1.21 0.58 Binned composite 12100.00 3.77 25.50 0.84 -1.19 0.41 Binned composite 12300.00 3.82 25.65 0.74 -1.10 0.55 Binned composite 12500.00 3.88 25.80 0.73 -1.15 0.43 Binned composite 12700.00 3.73 25.36 0.78 -1.14 0.39 Binned composite 12900.00 3.69 25.26 0.78 -1.33 0.12 Binned composite 13100.00 3.66 25.17 0.78 -1.26 0.15 Binned composite 13300.00 3.60 24.97 0.77 -1.25 0.10 Binned composite 13500.00 3.71 25.33 0.98 -1.26 0.14 Binned composite 13700.00 3.94 25.98 0.84 -1.16 0.35 Binned composite 13900.00 3.92 25.93 0.97 -1.27 0.20 Binned composite 14072.59 3.83 25.67 0.90 -1.17 0.23 GeoB9307-3, unbinned 14172.59 3.88 25.81 0.91 -1.11 0.31 GeoB9307-3, unbinned 14275.18 3.83 25.68 0.93 -1.08 0.30 GeoB9307-3, unbinned 14380.35 4.02 26.22 0.97 -1.14 0.34 GeoB9307-3, unbinned 14488.11 3.93 25.95 1.04 -1.26 0.16 GeoB9307-3, unbinned 14598.44 3.99 26.14 0.97 -1.11 0.34 GeoB9307-3, unbinned 14711.33 3.74 25.40 0.93 -0.94 0.35 GeoB9307-3, unbinned 14826.77 3.57 24.88 0.84 -1.29 -0.13 GeoB9307-3, unbinned 14944.73 3.43 24.46 0.78 -1.01 0.05 GeoB9307-3, unbinned 15065.20 3.67 25.19 0.85 -0.95 0.26 GeoB9307-3, unbinned 15188.14 3.65 25.15 0.90 -1.08 0.10 GeoB9307-3, unbinned 15313.51 3.83 25.67 0.90 -1.08 0.20 GeoB9307-3, unbinned 15441.30 3.50 24.67 0.93 -0.88 0.18 GeoB9307-3, unbinned 15571.45 3.93 25.96 0.84 -0.66 0.66 GeoB9307-3, unbinned 15703.92 3.81 25.61 0.89 -0.81 0.43 GeoB9307-3, unbinned 15838.68 3.76 25.47 0.87 -0.80 0.41 GeoB9307-3, unbinned 15975.66 3.47 24.58 0.93 -0.95 0.07 GeoB9307-3, unbinned 16114.81 3.75 25.44 1.06 -0.87 0.32 GeoB9307-3, unbinned 16256.07 3.58 24.92 1.04 -999 -999 GeoB9307-3, unbinned 16399.39 3.77 25.49 0.97 -0.50 0.68 GeoB9307-3, unbinned 16691.91 3.32 24.09 1.34 -0.79 0.08 GeoB9307-3, unbinned 16840.98 3.18 23.62 1.01 -0.64 0.12 GeoB9307-3, unbinned 16991.81 3.50 24.68 1.17 -0.67 0.31 GeoB9307-3, unbinned 17144.32 3.63 25.07 1.25 -0.72 0.34 GeoB9307-3, unbinned 17298.44 3.46 24.53 1.36 -0.63 0.32 GeoB9307-3, unbinned