Atlantic Deglacial Mg/Ca SST and d18Osw Reconstructions ----------------------------------------------------------------------- World Data Center for Paleoclimatology, Boulder and NOAA Paleoclimatology Program ----------------------------------------------------------------------- NOTE: PLEASE CITE ORIGINAL REFERENCE WHEN USING THIS DATA!!!!! NAME OF DATA SET: Atlantic Deglacial Mg/Ca SST and d18Osw Reconstructions LAST UPDATE: 5/2011 (Original receipt by WDC Paleo) CONTRIBUTORS: Carlson, A.E., D.W. Oppo, R.E. Came, A.N. LeGrande, L.D. Keigwin, and W.B. Curry. IGBP PAGES/WDCA CONTRIBUTION SERIES NUMBER: 2011-066 WDC PALEO CONTRIBUTION SERIES CITATION: Carlson, A.E., et al. 2011. Atlantic Deglacial Mg/Ca SST and d18Osw Reconstructions. IGBP PAGES/World Data Center for Paleoclimatology Data Contribution Series # 2011-066. NOAA/NCDC Paleoclimatology Program, Boulder CO, USA. ORIGINAL REFERENCE: Carlson, A.E., D.W. Oppo, R.E. Came, A.N. LeGrande, L.D. Keigwin, and W.B. Curry. 2008. Subtropical Atlantic salinity variability and Atlantic meridional circulation during the last deglaciation. Geology, Vol. 36, pp. 991-994. ABSTRACT: During the last deglaciation (ca. 21-10 ka), freshening of the North Atlantic surface likely caused reductions in Atlantic meridional overturning circulation (AMOC); the mechanisms related to AMOC recovery remain poorly understood. Here we present three new deglacial surface temperature and d18Oseawater (d18Osw) reconstructions from the western subtropical North and South Atlantic. Similarities to tropical Caribbean and western Atlantic d18Osw records suggest that a salty surface water mass accumulated in the western Atlantic from 27°S to 33°N during periods of reduced AMOC. However, d18Osw decreases led deep AMOC resumption by hundreds of years. We suggest that the northward export of salt previously trapped in the western Atlantic resulted in the early establishment of a shallow overturning circulation that eventually culminated in deep AMOC resumption, implying that AMOC may constitute a self-limiting system. ADDITIONAL REFERENCES: Anand, P., H. Elderfield, and M.H. Conte. 2003. Calibration of Mg/Ca thermometry in planktonic foraminifera from a sediment trap time series. Paleoceanography, v. 18, doi: 10.1029/2002PA000846. Dekens, P.S., D.W. Lea, D.K. Pak, and H.J. Spero. 2002. Core top calibration of Mg/Ca in tropical foraminifera: Refining paleotemperature estimation. Geochemistry, Geophysics, Geosystems, v. 3, doi: 10.1029/2001GC000200. GEOGRAPHIC REGION: Atlantic Ocean PERIOD OF RECORD: 21-10 KYrBP FUNDING SOURCES: Woods Hole Oceanographic Institution (WHOI) Postdoctoral Scholarship, WHOI Ocean Climate Change Institute, US National Science Foundation. DESCRIPTION: Reconstructed foraminiferal calcification temperature and d18Oseawater from three western subtropical North and South Atlantic sediment cores. Core OCE326-GGC5 is located on the Bermuda Rise, KNR140–51GGC on the Blake Outer Ridge, and KNR159–5–36GGC along the Brazilian margin. For the Blake Outer Ridge and the Brazilian margin cores, d18Ocalcite and Mg/Ca of the planktonic foraminifera Globigerinoides ruber (white) were measured. Mg/Ca was converted to calcification temperature (CT) for these two cores using a species-specific (G. ruber) core top calibration for the Atlantic basin (Dekens et al., 2002): Mg/Ca (mmol/mol) = 0.38*exp(0.09*CT) For Bermuda Rise core GGC5, d18Ocalcite and Mg/Ca of the planktonic foraminifera Globorotalia inflata were measured. A new Mg/Ca-CT calibration, following Anand et al. (2003) and Dekens et al. (2002), was developed for this core: Mg/Ca (mmol/mol) = 0.299*exp[0.09*(CT-0.61*D)] where D is the core water depth in km. Core Locations: OCE326-GGC5, Bermuda Rise: 33°42'N, 57°35'W, 4550 m depth KNR140-51GGC, Blake Outer Ridge: 32°47'N, 76°17'W, 1790 m depth KNR159–5–36GGC, Brazilian margin: 27°31'S, 46°28'W, 1268 m depth DATA: 1. Radiocarbon dates (reservoir corrected using CALIB 5.0.2 database) used in age model reconstruction. Calibrated age in calendar years before present. Delta-R is 0 for GGC5 and 51GGC and 160 yrs for 36GGC. Core Depth(cm) 14Cage Error Calib.Age 2-sigma error GGC5 65 5420 60 6240 70 GGC5 97 9650 40 11130 70 GGC5 112 10450 55 12390 260 GGC5 127 11900 50 13770 120 GGC5 137 12250 50 14130 180 GGC5 137 12300 50 14290 280 GGC5 161 12400 50 14460 330 GGC5 207 13900 150 16560 500 GGC5 221 14350 65 17150 440 GGC5 257 14800 80 18070 440 GGC5 261 15100 70 18540 140 GGC5 400 16450 80 19640 180 GGC5 407 16800 90 20000 200 51GGC 210 6910 55 7760 100 51GGC 280 9700 55 11150 80 51GGC 290 9800 55 11220 100 51GGC 300 10300 60 12170 220 51GGC 310 10950 65 12930 100 51GGC 320 11550 60 13410 150 51GGC 330 11850 100 13680 240 51GGC 350 12750 85 15040 330 51GGC 360 13900 85 16560 410 51GGC 370 14350 80 17170 470 51GGC 380 17700 110 20910 390 51GGC 400 19800 130 23710 440 51GGC 410 23200 190 25120 500 36GGC 1 1180 30 1110 60 36GGC 16 2610 60 2770 90 36GGC 28 3890 40 4320 100 36GGC 40 5440 35 6240 50 36GGC 56 7950 50 8820 180 36GGC 60 8890 50 10040 150 36GGC 68 10040 45 11540 220 36GGC 80 10840 50 12850 50 36GGC 88 11640 50 13500 150 36GGC 92 11890 60 13760 150 36GGC 104 12990 60 15370 310 36GGC 112 13090 60 15500 330 36GGC 141 14290 120 17160 600 36GGC 148 15490 65 18800 120 36GGC 200 18740 95 22300 180 2. Core 51GGC foraminiferal Mg/Ca, SST, and d18Osw Column 1: Depth (cm) Column 2: Age (kyBP) Column 3: Mg/Ca Globigerinoides ruber (white) (mmol/mol) Column 4: SST (°C) Column 5: d18O calcite Column 6: d18O sea water Depth Age Mg/Ca SST d18Oc d18Osw 10 0.37 -1.62 20 0.74 -1.70 30 1.11 -1.82 40 1.48 -1.85 50 1.85 -1.76 60 2.22 -1.69 70 2.59 -1.59 80 2.96 -1.63 90 3.33 -1.55 100 3.70 -1.55 110 4.06 -1.45 120 4.43 -1.54 130 4.80 -1.51 140 5.17 -1.50 150 5.54 -1.48 160 5.91 -1.59 170 6.28 -1.56 180 6.65 -1.59 190 7.02 -1.62 200 7.39 -1.85 210 7.76 4.46 27.38 -1.64 0.71 220 8.24 4.96 28.54 -1.45 1.37 230 8.73 4.56 27.62 -1.34 0.89 240 9.21 4.24 26.79 -1.42 0.79 250 9.70 4.75 28.06 -1.30 0.89 260 10.18 4.56 27.60 -1.33 1.11 270 10.67 4.16 26.60 -1.26 0.54 280 11.15 4.06 26.32 -1.33 0.62 282 11.16 4.16 26.59 -1.28 0.63 286 11.19 3.90 25.88 -1.16 0.51 288 11.21 3.79 25.55 -1.10 0.81 290 11.22 4.21 26.73 -1.11 0.86 294 11.60 3.96 26.04 -1.22 0.51 298 11.98 3.82 25.63 -1.11 0.45 300 12.17 3.75 25.45 -0.92 0.90 302 12.32 4.60 27.71 -0.70 1.39 306 12.62 3.74 25.42 -0.60 1.02 310 12.93 3.79 25.54 -0.46 1.14 312 13.03 3.40 24.33 -0.31 1.08 316 13.22 4.20 26.70 -0.24 1.73 320 13.41 4.04 26.27 -0.33 1.45 324 13.52 3.34 24.15 -0.57 0.72 328 13.63 3.42 24.43 -0.57 0.48 330 13.68 3.96 26.04 -0.55 1.35 332 13.82 3.68 25.22 -0.41 0.97 336 14.09 3.54 24.78 -0.47 0.89 340 14.36 4.19 26.67 -0.36 1.18 342 14.50 3.70 25.29 -0.30 1.20 344 14.63 3.63 25.09 -0.40 1.09 348 14.90 3.46 24.55 -0.67 0.40 350 15.04 4.54 27.55 -0.61 0.83 352 15.34 4.91 28.42 -0.32 1.92 356 15.95 -0.13 360 16.56 4.47 27.39 -0.13 1.28 364 16.81 4.29 26.94 -0.26 1.56 368 17.05 3.54 24.78 -0.07 0.83 370 17.17 4.73 28.02 -0.06 1.95 372 17.92 3.99 26.13 -0.03 1.37 376 19.42 4.28 26.92 -0.11 1.14 380 20.91 4.13 26.95 0.32 1.77 390 22.31 3.61 25.02 0.25 1.18 400 23.71 3.66 25.17 0.25 1.39 410 25.12 3.84 25.69 0.57 1.72 3. Core GGC5 foraminiferal Mg/Ca, CT, and d18Osw Column 1: Depth (cm) Column 2: Age (kyBP) Column 3: Mg/Ca Globorotalia inflata (mmol/mol) Column 4: Calcification Temperature (°C) Column 5: d18O calcite Column 6: d18O sea water Depth Age Mg/Ca CT d18Oc d18Osw 6 0.57 0.94 15.75 0.88 0.99 22 2.1 1.07 17.26 0.74 1.16 42 4.01 1 16.49 0.61 0.86 64 6.11 0.96 15.99 0.9 1.03 72.5 7.33 1.05 16.95 0.69 0.95 77.5 8.08 1.21 18.54 0.58 1.13 82.5 8.83 1.2 18.48 0.36 0.85 87.5 9.58 1.58 18.51 0.38 0.8 92.5 10.33 1.39 17.05 0.4 0.41 97.5 11.05 1.5 17.96 0.18 0.32 102.5 11.54 1.45 17.55 0.37 0.4 107.5 12.04 0.82 14.27 0.78 0.11 112.5 12.53 0.79 13.78 1.83 1.03 117.5 13.02 0.83 14.39 1.78 1.07 122.5 13.52 0.92 15.56 1.22 0.71 127.5 13.99 1.01 16.53 0.66 0.3 132.5 14.25 0.84 14.58 1.13 0.31 139 14.51 0.85 14.69 1.34 0.5 163 14.76 0.61 10.98 2.17 0.55 169 15.04 0.62 11.2 1.98 0.39 173 15.23 0.75 13.28 2.03 0.86 179 15.51 0.82 14.22 2.01 1.03 185 15.79 0.92 15.56 1.08 0.36 191 16.08 0.93 15.64 1.54 0.82 193.5 16.17 0.89 15.11 1.55 0.72 195 16.26 0.8 13.95 1.58 0.5 201.5 16.51 0.89 15.23 2.23 1.41 209.5 16.75 0.71 12.59 2.64 1.26 217 17.05 0.77 13.62 2.77 1.59 225 17.26 0.73 13.01 2.47 1.15 243 17.52 0.68 12.22 2.85 1.35 257 17.72 0.82 14.26 3.04 1.95 261 18.06 0.89 15.19 1.9 1 287 18.24 0.9 15.32 1.68 0.8 305 18.52 0.9 15.26 1.75 0.86 321 18.76 0.66 11.78 1.47 -0.17 337 19 1.23 18.74 1.68 1.46 353 19.25 0.73 12.93 1.68 0.21 385 19.51 0.87 14.97 2.07 1 401 19.68 0.93 15.64 1.77 0.83 403 19.79 0.83 14.34 1.81 0.6 405 19.91 0.84 14.49 1.72 0.53 4. Core 36GGC foraminiferal Mg/Ca, SST, and d18Osw Column 1: Depth (cm) Column 2: Age (kyBP) Column 3: Mg/Ca Globigerinoides ruber (white) (mmol/mol) Column 4: SST (°C) Column 5: d18O calcite Column 6: d18O sea water Depth Age Mg/Ca SST d18Oc d18Osw 1 1.11 -1.08 4 1.44 -0.91 8 1.88 -0.87 12 2.32 -0.94 16 2.77 -1.01 20 3.28 -0.68 24 3.80 -0.81 28 4.32 -0.61 32 4.96 -0.72 36 5.60 -0.84 40 6.24 -0.93 44 6.89 -0.61 48 7.53 -0.66 52 8.17 -0.48 56 8.82 -0.64 60 9.72 3.65 25.15 -0.23 1.55 64 10.63 3.64 25.11 -0.16 1.50 68 11.54 3.78 25.52 -0.17 1.52 72 11.98 3.76 25.46 -0.33 1.33 76 12.41 3.83 25.66 -0.24 1.44 80 12.85 3.69 25.24 -0.25 1.31 84 13.17 3.71 25.33 0.32 1.90 88 13.50 3.79 25.54 0.18 1.70 92 13.76 3.54 24.81 0.17 1.52 96 14.30 3.25 23.85 0.20 1.29 100 14.83 3.35 24.17 0.20 1.32 104 15.37 3.01 22.99 0.38 1.23 108 15.43 3.11 23.37 0.34 1.27 112 15.50 3.17 23.56 0.38 1.34 116 15.73 3.43 24.45 0.68 1.81 120 15.97 3.38 24.30 0.25 1.59 124 16.21 3.21 23.70 0.03 1.65 128 16.45 3.41 24.39 0.48 1.78 132 16.68 3.53 24.76 0.74 2.13 136 16.92 3.05 23.12 0.75 1.55 140 17.16 3.06 23.17 0.79 1.59 144 17.98 3.91 25.89 0.83 2.15 148 18.80 3.44 24.48 0.29 1.29 152 19.07 3.23 23.77 0.40 1.18 156 19.34 3.16 23.55 0.53 1.19 160 19.61 3.38 24.28 0.66 1.49 164 19.88 3.51 24.70 0.49 1.42 168 20.15 3.11 23.34 0.54 1.21 172 20.41 2.92 22.67 0.39 0.93 176 20.68 3.66 25.17 0.28 1.35 180 20.95 3.36 24.23 0.47 1.35 188 21.49 3.17 23.58 0.46 1.18 196 22.03 3.10 23.33 0.67 1.33 200 22.30 3.13 23.43 0.39 1.07 208 22.84 3.10 23.34 0.72 1.38