Northeast Atlantic SU81-18 Deglacial 231Pa/230Th Data ----------------------------------------------------------------------- World Data Center for Paleoclimatology, Boulder and NOAA Paleoclimatology Program ----------------------------------------------------------------------- NOTE: PLEASE CITE ORIGINAL REFERENCE WHEN USING THIS DATA!!!!! NAME OF DATA SET: Northeast Atlantic SU81-18 Deglacial 231Pa/230Th Data LAST UPDATE: 11/2008 (Original receipt by WDC Paleo) CONTRIBUTOR: Jeanne Gherardi Scao, University of Bergen IGBP PAGES/WDCA CONTRIBUTION SERIES NUMBER: 2008-118 WDC PALEO CONTRIBUTION SERIES CITATION: Gherardi, J.-M., et al. 2008. Northeast Atlantic SU81-18 Deglacial 231Pa/230Th Data. IGBP PAGES/World Data Center for Paleoclimatology Data Contribution Series # 2008-118. NOAA/NCDC Paleoclimatology Program, Boulder CO, USA. ORIGINAL REFERENCE: Gherardi, J.-M., L. Labeyrie, J.F. McManus, R. Francois, L.C. Skinner, and E. Cortijo. 2005. Evidence from the Northeastern Atlantic basin for variability in the rate of the meridional overturning circulation through the last deglaciation. Earth and Planetary Science Letters, Vol. 240, Issues 3-4, pp. 710-723, 15 December 2005. doi:10.1016/j.epsl.2005.09.061 ABSTRACT: A first study from the subtropical western Atlantic, using 231Pa/230Th ratios as a kinematic proxy for deep water circulation, provided compelling evidence for a strong link between climate and the rate of Meridional Overturning Circulation (MOC) over the last deglaciation. However, these results warrant confirmation from additional locations and water depths because the interpretation of the sedimentary 231Pa/230Th ratio in terms of circulation vigor can be biased by variations in particle flux and composition. We have measured 231Pa/230Th in a core from the Iberian margin, in the Northeastern Atlantic basin, and have compared these new results to the data from the western Atlantic basin. We find that the reduction in the circulation during H1 and YD and the subsequent increases first recognized in the sediment deposited on Bermuda Rise are also evident in the eastern basin, in a totally different sedimentary regime, confirming that sedimentary 231Pa/230Th ratios record basin-wide changes in deep water circulation. However, some differences between the eastern and western records are also recognized, providing preliminary evidence to differentiate between renewal rates in the two North Atlantic basins and between shallower and deeper overturning. Our results suggest the possible existence of two sources of Glacial North Atlantic Intermediate Deep Water (GNAIW), one in the south Labrador Sea and another west of Rockall Plateau. Both sources contributed to the meridional overturning but the two had different sensitivity to meltwater from the Laurentide and the Fennoscandian ice sheets during the deglaciation. These results indicate that additional information on the geometry and strength of the ventilation of the deep Atlantic can be obtained by contrasting the evolution of sediment 231Pa/230Th in different sections of the Atlantic Ocean. GEOGRAPHIC REGION: Iberian margin, northeastern Atlantic PERIOD OF RECORD: 21KYRBP - present FUNDING SOURCES: US National Science Foundation grants OCE-0099176 and INT-0233483, French programmes VAGALAM, CEA, and CNRS, and the Gary Comer Science and Education Foundation. DESCRIPTION: Sedimentary 231Pa/230Th ratios from core SU81-18 on the Iberian margin of the northeastern Atlantic, interpreted as a proxy for Atlantic deep water circulation. Core SU81-18: 37° 46'N, 10° 11'W, 3135m depth. DATA: 1. 14C AMS data Column 1: Depth, cm. Column 2: Species Column 3: 14C age (ka BP) Column 4: 14C age error (a) Column 5: Calendar age (ka BP) Column 6: Mean error (2 sigma) Table 1: SU81-18 14C AMS data points and calculated calendar ages using a 400 yr reservoir age, from Waelbroeck et al. Three additional pointers were added (grey lines) using a correlation with d18O of ice from GISP 2 in order to better constrain the core top and the Younger Dryas. Depth Species 14Cage Error Cal.age Mean error 0 0.00 12.5 G. bulloides 1440 190 0.81 0.27 29.75 G. bulloides 1810 80 1.63 0.30 49.75 G. bulloides 3450 100 3.34 0.11 69.5 G. bulloides 4940 240 5.02 0.35 89.75 G. bulloides 5640 140 6.15 0.20 111 G. bulloides 7190 140 7.71 0.14 129.5 G. bulloides 7990 120 8.72 0.36 140 G. bulloides 9160 130 9.72 0.16 149.5 G. bulloides 9760 130 10.34 0.19 170 11.83 189.5 G. bulloides 11080 140 12.53 0.21 200 12.80 208.5 G. bulloides 12160 200 13.49 0.24 229.5 G. bulloides 12660 170 14.19 0.19 249.5 G. bulloides 12860 150 14.86 0.46 260 G. bulloides 13100 170 15.13 0.53 280 G. bulloides 13980 190 16.12 0.30 299 G. bulloides 14350 180 16.61 0.31 310 G. bulloides 14890 230 16.89 0.36 320 G. bulloides 14340 170 17.14 0.54 329.5 G. bulloides 14990 190 17.36 0.33 360 G. bulloides 15630 220 18.08 0.37 400 G. bulloides 17510 270 19.66 0.84 521 G. bulloides 21250 280 23.87 0.84 2. Oxygen isotope data Table 3: SU81-18 oxygen isotopes data from G. bulloides (d18O in PDB) Column 1: Calendar age (ka BP) Column 2: G. bulloides d18O (per mil PDB) Cal.Age G.bull. d18O 0.61 -0.08 1.14 0.01 1.66 0.04 2.53 0.06 3.4 0.33 4.22 0.36 5.04 0.35 5.59 0.32 6.15 0.35 6.87 0.36 7.59 0.34 8.14 0.59 8.62 0.57 8.69 0.54 9.2 0.34 9.62 0.25 9.72 0.06 10.05 0.57 10.38 0.57 10.45 0.88 10.74 0.94 11.1 0.94 11.83 1.54 12.18 1.73 12.54 1.41 12.79 1.47 13.36 1.12 13.8 1.07 14.03 1.3 14.25 0.96 14.52 0.95 14.79 2.03 14.96 2.32 15.14 2.23 15.36 2.3 15.59 2.2 15.82 2.01 16.05 2.13 16.21 2.53 16.36 2.46 16.51 2.56 16.66 2.63 16.77 2.57 16.86 2.42 16.98 2.8 17.07 2.63 17.2 2.85 17.38 2.83 17.5 3.09 17.61 2.77 17.72 2.56 17.83 2.4 17.91 2.35 18.24 2.02 18.63 1.85 19.01 1.99 19.4 2.08 19.59 2.27 19.98 2.1 20.37 1.9 20.76 1.82 3. 230Th/231Pa ratios Table 4: SU81-18 all 230Th, 231Pa and excess sedimentary ratio decay corrected from deposition time 231Pa(xs,0)/230Th(xs,0) Column 1: Depth (cm.) Column 2: Calendar age (ka BP) Column 3: 230Th (dpm/g) Column 4: 231Pa (dpm/g) Column 5: 231Pa(xs,0) / 230Th(xs,0) Column 6: St. errors (2 sigma) Depth Cal.Age 230Th 231Pa 231Pa/230Th St. errors 8 0.43 3 0.168 0.061 0.003 19 1.16 3.52 0.193 0.059 0.002 25 1.57 2.96 0.174 0.066 0.004 27 1.71 2.98 0.191 0.074 0.003 45 2.98 3.01 0.138 0.047 0.002 45 2.98 3.05 0.194 0.074 0.005 65 4.43 3.19 0.173 0.061 0.003 85 5.88 3.23 0.186 0.067 0.003 107 7.44 3.63 0.203 0.064 0.003 127 8.79 3.88 0.208 0.061 0.003 145 9.94 3.4 0.193 0.067 0.004 145 9.94 3.33 0.178 0.063 0.002 166 11.18 3.3 0.161 0.055 0.003 167 11.24 3.3 0.158 0.053 0.003 176 11.74 3.22 0.196 0.078 0.005 185 12.21 3.28 0.197 0.077 0.006 186 12.26 3.33 0.189 0.071 0.003 193 12.62 3.16 0.176 0.07 0.003 195 12.72 3.06 0.166 0.067 0.004 197 12.81 3.22 0.181 0.071 0.003 204 13.14 2.89 0.154 0.066 0.003 235 14.46 2.55 0.142 0.071 0.005 245 14.83 2.57 0.143 0.071 0.005 252 15.08 2.69 0.158 0.08 0.006 256 15.21 2.85 0.167 0.079 0.004 264 15.48 2.81 0.169 0.081 0.005 267 15.57 2.85 0.166 0.078 0.005 273 15.76 2.5 0.154 0.084 0.003 276 15.85 2.96 0.173 0.077 0.003 284 16.09 2.84 0.157 0.08 0.005 287 16.18 2.9 0.162 0.072 0.003 296 16.43 2.86 0.147 0.062 0.003 311 16.84 2.63 0.127 0.055 0.003 327 17.27 2.67 0.126 0.053 0.003 344 17.73 2.87 0.127 0.047 0.002 351 17.93 2.71 0.124 0.047 0.004 361 18.23 2.69 0.125 0.05 0.003 374 18.66 3.23 0.149 0.049 0.002 396 19.49 2.71 0.126 0.05 0.004 404 19.84 2.76 0.123 0.047 0.004 424 20.86 3.21 0.146 0.051 0.004 4. Flux data Table 5: SU81-18 Th-normalized flux data Column 1: Calendar age (ka BP) Column 2: Th-normalized flux (g/cm2/ky) Cal.Age Flux 0.43 4.24 0.96 4.31 0.96 4.29 1.16 3.28 1.57 4.17 1.71 4.13 2.98 3.92 2.98 3.96 4.43 3.71 5.88 3.6 7.44 2.96 8.79 2.65 9.94 3.3 9.94 3.71 10.37 3.89 10.66 3.77 11.18 3.67 11.18 3.4 11.24 3.6 11.74 3.87 11.74 3.85 12.16 3.71 12.21 3.75 12.26 3.68 12.62 4 12.72 4.13 12.81 3.88 13.14 4.58 13.98 5.35 13.98 5.38 14.46 5.54 14.83 5.15 15.08 5.05 15.21 4.49 15.48 4.61 15.57 4.46 15.76 5.09 15.85 4.27 16.09 6.35 16.18 4.31 16.35 4.58 16.43 4.29 16.84 5.12 17.27 5.03 17.73 4.39 17.93 5.24 18.23 5.11 18.66 4.19 18.9 5.05 19.49 5.01 19.84 4.94 20.32 4.42 20.86 3.95 21.47 3.64