# 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-gb9307-3.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 # Location: Indian Ocean # Country: # Northernmost_Latitude: -18.5525 # Southernmost_Latitude: -18.5525 # Easternmost_Longitude: 37.3688 # Westernmost_Longitude: 37.3688 # Elevation: -542 #--------------------------------------- # Data_Collection # Collection_Name: GeoB9307-3 Weldeab2014 # First_Year: 17300 # Last_Year: 100 # Time_Unit: cal yr BP # Core_Length: 6.33 # 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 # #--------------------------------------- # 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 99.55 3.74 25.41 -999 -2.17 -999 8 602.09 3.99 26.12 0.79 -2.08 0.17 13.00 1087.81 3.76 25.46 0.79 -2.20 -0.09 18.00 1557.10 3.71 25.32 1.20 -2.16 -0.07 23.00 2010.34 3.89 25.85 0.83 -1.97 0.22 28.00 2447.89 3.70 25.29 0.82 -1.96 0.12 33.00 2870.14 4.06 26.32 1.06 -2.06 0.22 38.00 3277.44 3.94 25.98 0.87 -1.97 0.24 43.00 3670.15 3.84 25.71 0.77 -2.12 0.03 48.00 4048.65 3.98 26.09 0.84 -2.02 0.21 53.00 4413.28 3.69 25.25 0.91 -2.05 0.00 58.00 4764.39 3.80 25.59 0.76 -2.17 -0.04 63.00 5102.34 4.08 26.38 0.77 -2.13 0.15 68.00 5427.46 3.92 25.93 0.93 -2.12 0.06 73.00 5740.09 3.95 26.01 0.84 -2.01 0.18 78.00 6040.58 4.07 26.36 0.74 -2.04 0.22 83.00 6329.26 3.76 25.47 0.94 -1.94 0.14 88.00 6606.44 4.33 27.04 0.82 -2.22 0.17 93.00 6872.46 3.65 25.13 0.91 -2.09 -0.09 98.00 7127.64 4.16 26.59 0.83 -2.11 0.18 103.00 7372.30 3.82 25.64 0.82 -2.02 0.07 108.00 7606.75 3.86 25.75 0.82 -2.03 0.08 113.00 7831.30 4.15 26.58 0.86 -2.04 0.23 118.00 8046.25 3.99 26.12 0.86 -1.98 0.18 123.00 8251.91 3.96 26.05 0.90 -1.90 0.23 128.00 8448.57 4.09 26.40 0.91 -1.95 0.24 133.00 8636.53 3.97 26.08 0.96 -2.03 0.08 138.00 8816.09 4.00 26.17 0.95 -2.00 0.11 143.00 8987.52 3.78 25.52 0.87 -1.95 0.01 148.00 9151.11 3.99 26.13 0.91 -1.91 0.17 153.00 9307.15 3.97 26.06 0.91 -1.82 0.23 158.00 9455.90 3.88 25.82 0.81 -1.77 0.21 163.00 9597.63 4.17 26.62 0.90 -1.85 0.28 168.00 9732.62 4.02 26.21 0.84 -1.91 0.12 173.00 9861.13 4.11 26.46 0.80 -1.88 0.19 178.00 9983.42 4.06 26.33 0.87 -1.81 0.21 183.00 10099.75 4.50 27.47 0.90 -1.88 0.37 188.00 10210.37 4.10 26.42 0.80 -1.80 0.22 193.00 10315.52 3.93 25.96 0.79 -1.80 0.11 198.00 10415.46 4.15 26.55 0.84 -1.79 0.24 203.00 10510.42 4.26 26.85 0.77 -1.69 0.39 208.00 10600.65 4.03 26.23 0.77 -1.74 0.20 213.00 10686.37 4.26 26.86 0.81 -1.71 0.34 218.00 10767.81 4.10 26.43 0.81 -1.66 0.30 223.00 10845.21 4.13 26.52 0.82 -1.78 0.19 228.00 10918.79 4.25 26.82 0.75 -1.67 0.36 233.00 10988.76 4.03 26.25 0.80 -1.70 0.19 238.00 11055.34 4.15 26.56 0.76 -1.37 0.58 243.00 11118.73 3.74 25.41 0.72 -1.51 0.20 248.00 11179.16 4.14 26.54 0.77 -1.42 0.51 258.00 11291.90 4.13 26.52 0.91 -1.15 0.77 263.00 11344.61 3.78 25.52 0.73 -1.17 0.53 268.00 11395.13 3.57 24.90 0.84 -1.15 0.42 273.00 11443.67 3.96 26.05 0.78 -1.14 0.66 278.00 11490.40 3.91 25.89 0.71 -999 -999 283.00 11535.49 4.00 26.16 0.78 -1.11 0.70 288.00 11579.14 3.70 25.29 0.79 -999 -999 298.00 11662.77 3.86 25.75 0.84 -1.30 0.41 303.00 11703.09 3.95 26.01 0.68 -1.02 0.73 308.00 11742.62 3.50 24.66 0.97 -1.10 0.37 313.00 11781.53 4.03 26.22 0.92 -1.10 0.70 318.00 11819.97 -999 -999 -999 -1.19 -999 328.00 11896.05 3.59 24.95 0.90 -999 -999 333.00 11933.97 3.88 25.82 0.70 -1.11 0.58 338.00 11972.00 3.91 25.91 0.68 -1.16 0.55 343.00 12010.28 3.83 25.66 0.89 -1.16 0.49 348.00 12048.93 3.45 24.52 1.00 -1.10 0.30 353.00 12088.09 3.72 25.35 0.66 -0.95 0.62 358.00 12127.88 3.97 26.08 -999 -1.06 0.65 363.00 12168.41 4.07 26.35 0.77 -1.16 0.61 368.00 12209.81 3.73 25.38 0.63 -1.01 0.55 373.00 12252.18 4.08 26.36 0.72 -0.94 0.82 378.00 12295.64 3.72 25.34 1.05 -0.97 0.57 383.00 12340.29 3.88 25.82 0.74 -999 -999 388.00 12386.23 -999 -999 -999 -1.12 -999 393.00 12433.56 3.85 25.73 0.66 -999 -999 398.00 12482.37 4.00 26.16 0.68 -999 -999 403.00 12532.76 3.63 25.09 0.59 -1.07 0.39 408.00 12584.80 3.74 25.41 0.77 -0.99 0.54 413.00 12638.58 3.67 25.20 0.73 -1.10 0.37 423.00 12751.68 3.72 25.34 0.66 -0.90 0.59 428.00 12811.13 3.64 25.11 0.74 -1.13 0.30 433.00 12872.62 4.00 26.15 0.78 -1.58 0.06 438.00 12936.20 3.52 24.75 0.81 -1.25 0.09 443.00 13001.94 3.62 25.04 0.78 -1.16 0.24 448.00 13069.89 3.64 25.12 0.78 -1.21 0.19 453.00 13140.09 3.64 25.10 0.71 -1.28 0.11 458.00 13212.61 3.52 24.74 0.78 -1.15 0.16 463.00 13287.47 3.56 24.87 0.76 -1.27 0.05 468.00 13364.73 3.50 24.67 0.71 -1.24 0.04 473.00 13444.43 3.45 24.52 1.00 -1.25 -0.02 478.00 13526.58 3.70 25.30 0.90 -1.24 0.15 483.00 13611.23 3.82 25.65 0.88 -1.15 0.30 488.00 13698.39 3.88 25.81 0.87 -1.06 0.41 493.00 13788.09 3.86 25.75 0.80 -1.25 0.19 498.00 13880.35 3.78 25.54 0.98 -1.26 0.13 503.00 13975.18 3.96 26.05 0.91 -1.29 0.19 508.00 14072.59 3.83 25.67 0.90 -1.17 0.23 513.00 14172.59 3.88 25.81 0.91 -1.11 0.31 518.00 14275.18 3.83 25.68 0.93 -1.08 0.30 523.00 14380.35 4.02 26.22 0.97 -1.14 0.34 528.00 14488.11 3.93 25.95 1.04 -1.26 0.16 533.00 14598.44 3.99 26.14 0.97 -1.11 0.34 538.00 14711.33 3.74 25.40 0.93 -0.94 0.35 543.00 14826.77 3.57 24.88 0.84 -1.29 -0.13 548.00 14944.73 3.43 24.46 0.78 -1.01 0.05 553.00 15065.20 3.67 25.19 0.85 -0.95 0.26 558.00 15188.14 3.65 25.15 0.90 -1.08 0.10 563.00 15313.51 3.83 25.67 0.90 -1.08 0.20 568.00 15441.30 3.50 24.67 0.93 -0.88 0.18 573.00 15571.45 3.93 25.96 0.84 -0.66 0.66 578.00 15703.92 3.81 25.61 0.89 -0.81 0.43 583.00 15838.68 3.76 25.47 0.87 -0.80 0.41 588.00 15975.66 3.47 24.58 0.93 -0.95 0.07 593.00 16114.81 3.75 25.44 1.06 -0.87 0.32 598.00 16256.07 3.58 24.92 1.04 -999 -999 603.00 16399.39 3.77 25.49 0.97 -0.50 0.68 613.00 16691.91 3.32 24.09 1.34 -0.79 0.08 618.00 16840.98 3.18 23.62 1.01 -0.64 0.12 623.00 16991.81 3.50 24.68 1.17 -0.67 0.31 628.00 17144.32 3.63 25.07 1.25 -0.72 0.34 633.00 17298.44 3.46 24.53 1.36 -0.63 0.32