Eastern Equatorial Pacific 30KYr Alkenone SST Reconstructions ----------------------------------------------------------------------- World Data Center for Paleoclimatology, Boulder and NOAA Paleoclimatology Program ----------------------------------------------------------------------- NOTE: PLEASE CITE ORIGINAL REFERENCE WHEN USING THIS DATA!!!!! NAME OF DATA SET: Eastern Equatorial Pacific 30KYr Alkenone SST Reconstructions LAST UPDATE: 9/2011 (Original receipt by WDC Paleo) CONTRIBUTORS: Dubois, N., M. Kienast, C. Normandeau, and T.D. Herbert IGBP PAGES/WDCA CONTRIBUTION SERIES NUMBER: 2011-124 WDC PALEO CONTRIBUTION SERIES CITATION: Dubois, N., et al. 2011. Eastern Equatorial Pacific 30KYr Alkenone SST Reconstructions. IGBP PAGES/World Data Center for Paleoclimatology Data Contribution Series # 2011-124. NOAA/NCDC Paleoclimatology Program, Boulder CO, USA. ORIGINAL REFERENCE: Dubois, N., M. Kienast, C. Normandeau, and T.D. Herbert. 2009. Eastern equatorial Pacific cold tongue during the Last Glacial Maximum as seen from alkenone paleothermometry. Paleoceanography, 24, PA4207, doi:10.1029/2009PA001781. ABSTRACT: We present new alkenone-based sea surface temperature (SST) estimates from the eastern equatorial Pacific (EEP) for the last 30 kyr. By combining these new results with recently published records from the region, we reconstruct the spatial pattern of changes in SST during the Last Glacial Maximum (LGM). Alkenone-based SST estimates show a greater glacial cooling in the upwelling environment of the cold tongue than in sites located further north in the equatorial front and eastern Pacific Warm Pool. This result agrees with the paradigm of stronger glacial winds, increased upwelling, steeper zonal thermocline tilt, and stronger advection of cold water in the Peru Current. Furthermore, we investigate possible changes in glacial surface hydrography by using the alkenone-based SST reconstructions to correct planktonic foraminifera d18O for the temperature effect. After additional correction for the global ice volume effect, the residual changes in seawater d18O show a clear latitudinal pattern that would be consistent with a southward shift of the Intertropical Convergence Zone. We thus suggest that changes in sea surface salinities could explain contrasting SST reconstructions based on planktonic foraminifera d18O, which implied a weakening of the cold tongue. The controversial LGM dynamics of the EEP reconstructed by different proxies, i.e., a weakening or a strengthening of the cold tongue, highlight the necessity to better assess the influence of various biases on these proxies. ADDITIONAL REFERENCES: Benway, H.M., A.C. Mix, B.A. Haley, and G.P. Klinkhammer. 2006. Eastern Pacific Warm Pool paleosalinity and climate variability: 0-30 kyr. Paleoceanography, v. 21, PA3008, doi:10.1029/2005PA001208. Herbert, T.D., J.D. Schuffert, D. Thomas, C. Lange, A. Weinheimer, A. Peleo-Alampay, C. Lange, A. Weinheimer, A. Peleo-Alampay, and J.-C. Herguera. 1998. Depth and seasonality of alkenone production along the California margin inferred from a core top transect. Paleoceanography, v. 13, 263- 271. Kienast, M., S.S. Kienast, S.E. Calvert, T.I. Eglinton, G. Mollenhauer, R. François, and A. Mix. 2006. Eastern Pacific cooling and Atlantic overturning circulation during the last deglaciation. Nature, v. 443, 846?849, doi:10.1038/nature05222. Kienast, S.S., M. Kienast, A.C. Mix, S.E. Calvert, and R. François. 2007. Thorium-230 normalized particle flux and sediment focusing in the Panama Basin region during the last 30,000 years. Paleoceanography, v. 22, PA2213, doi:10.1029/2006PA001357. Lea, D.W., D.K. Pak, C.L. Belanger, H.J. Spero, M.A. Hall, and N.J. Shackleton. 2006. Paleoclimate history of Galapagos surface waters over the last 135,000 yr. Quat. Sci. Rev., v. 25, 1152-1167. doi:10.1016/j.quascirev.2005.11.010. Lea, D.W., D.K. Pak, and H.J. Spero. 2000. Climate impact of late quaternary equatorial Pacific sea surface temperature variations. Science, v. 289, 1719-1724, doi:10.1126/science.289.5485.1719. Martin, P.A., D.W. Lea, Y. Rosenthal, N.J. Shackleton, M. Sarnthein, and T. Papenfuss. 2002. Quaternary deep sea temperature histories derived from benthic foraminiferal Mg/Ca. Earth Planet. Sci. Lett., v. 198, 193-209. doi:10.1016/S0012-821X(02)00472-7. Prahl, F. G., L. A. Muehlhausen, and D. L. Zahnle. 1988. Further evaluation of longchain alkenones as indicators of paleoceanographic conditions. Geochim. Cosmochim. Acta, v. 52, 2303-2310, doi:10.1016/0016-7037(88)90132-9. GEOGRAPHIC REGION: Eastern Equatorial Pacific PERIOD OF RECORD: 30 KYrBP - present FUNDING SOURCES: NSERC Canada, US National Science Foundation (NSF), Canadian Institute for Advanced Research (CIFAR). DESCRIPTION: Reconstructed alkenone-based sea surface temperature from five eastern equatorial Pacific sediment cores covering the last 30 kyr BP. Cores ME0005A-27JC, ME0005A-43JC and TR163-31P were analyzed for alkenone unsaturation at Dalhousie University following standard laboratory procedures detailed by Kienast et al. (2006), whereas cores TR163-19P and TR163-22P where analyzed at Brown University following similar laboratory procedures detailed by Herbert et al. (1998). The age models for these cores were adopted as published in earlier studies (ME0005A-27JC from Kienast et al. 2007, ME0005A-43JC from Benway et al. 2006, TR163-19P from Lea et al. 2000, TR163-22P from Lea et al. 2006, TR163-31P from Martin et al. 2002). The alkenone unsaturation index UK037 is calculated as UK'37 = (C37:2)/(C37:3 + C37:2), where (C37:2) and (C37:3) are concentrations of the diunsaturated and triunsaturated C37 methyl alkenones. For conversion into temperature estimates, we used the culture calibration of Prahl et al. (1988) (UK'37 = 0.034T + 0.039). Replicate analyses of selected samples indicate an analytical precision of about ±0.01 UK'37 units (0.3°C). Core Locations: ME0005A-27JC: 1°51.20'S, 82°47.20'W, 2203 m water depth ME0005A-43JC: 7°51.35'N, 83°36.50'W, 1368 m water depth TR163-19P: 2°15.50'N, 90°57.10'W, 2348 m water depth TR163-22P: 0°30.90'N, 92°23.90'W, 2830 m water depth TR163-31P: 3°37.12'S, 83°58.24'W, 3205 m water depth DATA: 1. Core ME0005A-27JC UK'37 and UK-based SST. Age model from Kienast et al. (2007). Column 1: Core Column 2: Depth (cm) Column 3: Age (kyr BP) Column 4: UK'37 Column 5: SST (°C) Core Depth Age UK'37 SST ME0005A-27JC 4 1.21 0.861 24.19 ME0005A-27JC 6 1.56 0.859 24.11 ME0005A-27JC 8 1.91 0.863 24.24 ME0005A-27JC 10 2.26 0.873 24.52 ME0005A-27JC 22 4.38 0.849 23.82 ME0005A-27JC 26 5.08 0.858 24.07 ME0005A-27JC 28 5.44 0.875 24.59 ME0005A-27JC 30 5.79 0.856 24.03 ME0005A-27JC 32.5 6.23 0.853 23.93 ME0005A-27JC 36 6.85 0.853 23.95 ME0005A-27JC 38 7.2 0.872 24.5 ME0005A-27JC 40 7.55 0.855 24.01 ME0005A-27JC 42 7.88 0.855 24 ME0005A-27JC 44 8.19 0.853 23.95 ME0005A-27JC 48 8.81 0.836 23.44 ME0005A-27JC 52.5 9.51 0.838 23.49 ME0005A-27JC 58 10.36 0.847 23.76 ME0005A-27JC 62 10.98 0.843 23.65 ME0005A-27JC 66 11.6 0.835 23.4 ME0005A-27JC 68 11.91 0.824 23.09 ME0005A-27JC 69.5 12.14 0.816 22.86 ME0005A-27JC 71 12.37 0.834 23.37 ME0005A-27JC 72.5 12.61 0.818 22.92 ME0005A-27JC 74 12.84 0.804 22.49 ME0005A-27JC 76 13.15 0.811 22.7 ME0005A-27JC 77 13.3 0.806 22.55 ME0005A-27JC 79 13.61 0.809 22.65 ME0005A-27JC 82 14.08 0.813 22.77 ME0005A-27JC 84 14.39 0.805 22.53 ME0005A-27JC 86 14.7 0.815 22.83 ME0005A-27JC 88 15.01 0.803 22.48 ME0005A-27JC 90 15.32 0.829 23.25 ME0005A-27JC 92 15.62 0.784 21.91 ME0005A-27JC 94 15.91 0.793 22.16 ME0005A-27JC 96 16.21 0.786 21.98 ME0005A-27JC 98 16.5 0.793 22.19 ME0005A-27JC 99 16.65 0.789 22.05 ME0005A-27JC 100.5 16.87 0.785 21.93 ME0005A-27JC 101.5 17.02 0.791 22.12 ME0005A-27JC 104 17.39 0.797 22.29 ME0005A-27JC 106 17.68 0.823 23.05 ME0005A-27JC 108 17.98 0.795 22.24 ME0005A-27JC 110 18.27 0.784 21.92 ME0005A-27JC 112 18.57 0.796 22.26 ME0005A-27JC 114 18.86 0.801 22.4 ME0005A-27JC 116 19.16 0.821 23.01 ME0005A-27JC 122 20.07 0.818 22.93 ME0005A-27JC 132 21.68 0.823 23.07 ME0005A-27JC 142 23.29 0.807 22.6 ME0005A-27JC 152 24.89 0.797 22.3 ME0005A-27JC 171.5 28.03 0.805 22.52 ME0005A-27JC 174 28.69 0.836 23.43 ME0005A-27JC 176 29.05 0.843 23.64 ME0005A-27JC 177.5 29.32 0.833 23.36 ME0005A-27JC 179.5 29.68 0.843 23.64 2. Core ME0005A-43JC UK'37 and UK-based SST. Age model from Benway et al. (2006). Column 1: Core Column 2: Depth (cm) Column 3: Age (kyr BP) Column 4: UK'37 Column 5: SST (°C) Core Depth Age UK'37 SST ME0005A-43JC 11 2.31 0.96 27.08 ME0005A-43JC 25 4.87 0.954 26.91 ME0005A-43JC 28 5.25 0.949 26.76 ME0005A-43JC 34 5.83 0.949 26.76 ME0005A-43JC 44 6.81 0.943 26.59 ME0005A-43JC 47 7.1 0.943 26.59 ME0005A-43JC 53 7.69 0.942 26.56 ME0005A-43JC 65 8.86 0.942 26.55 ME0005A-43JC 71 9.44 0.929 26.18 ME0005A-43JC 76 9.93 0.925 26.05 ME0005A-43JC 79 10.22 0.932 26.26 ME0005A-43JC 84 10.71 0.928 26.14 ME0005A-43JC 87 11 0.919 25.87 ME0005A-43JC 90 11.29 0.92 25.92 ME0005A-43JC 93 11.6 0.92 25.9 ME0005A-43JC 96 11.91 0.918 25.86 ME0005A-43JC 99 12.22 0.924 26.03 ME0005A-43JC 102 12.54 0.915 25.77 ME0005A-43JC 108 13.16 0.91 25.62 ME0005A-43JC 111 13.47 0.919 25.88 ME0005A-43JC 114 13.79 0.911 25.63 ME0005A-43JC 117 14.1 0.919 25.88 ME0005A-43JC 121 14.52 0.915 25.76 ME0005A-43JC 124 14.83 0.916 25.79 ME0005A-43JC 127 15.14 0.9 25.31 ME0005A-43JC 132 15.65 0.906 25.49 ME0005A-43JC 135 15.92 0.901 25.36 ME0005A-43JC 138 16.19 0.889 25.01 ME0005A-43JC 141 16.46 0.904 25.43 ME0005A-43JC 144 16.73 0.902 25.38 ME0005A-43JC 147 17 0.887 24.95 ME0005A-43JC 151 17.36 0.913 25.7 ME0005A-43JC 155 17.72 0.892 25.1 ME0005A-43JC 158 17.99 0.906 25.49 ME0005A-43JC 161 18.26 0.914 25.75 ME0005A-43JC 164 18.53 0.913 25.69 ME0005A-43JC 171 19.16 0.906 25.49 ME0005A-43JC 173 19.34 0.901 25.34 ME0005A-43JC 176 19.61 0.9 25.33 ME0005A-43JC 178 19.79 0.911 25.65 ME0005A-43JC 180 19.97 0.913 25.72 ME0005A-43JC 183 20.24 0.907 25.52 ME0005A-43JC 187 20.58 0.916 25.79 ME0005A-43JC 191 20.87 0.911 25.65 ME0005A-43JC 193 21.02 0.91 25.62 ME0005A-43JC 202 21.68 0.913 25.69 ME0005A-43JC 208 22.12 0.913 25.72 ME0005A-43JC 211 22.3 0.897 25.24 ME0005A-43JC 214 22.48 0.917 25.81 ME0005A-43JC 217 22.65 0.905 25.47 ME0005A-43JC 221 22.89 0.925 26.06 ME0005A-43JC 227 23.24 0.911 25.64 ME0005A-43JC 231 23.51 0.894 25.15 ME0005A-43JC 234 23.72 0.908 25.56 ME0005A-43JC 237 23.93 0.884 24.85 ME0005A-43JC 241 24.34 0.886 24.92 ME0005A-43JC 243 24.57 0.904 25.44 ME0005A-43JC 246 24.92 0.891 25.05 3. Core TR163-19P UK'37 and UK-based SST. Age model from Lea et al. (2000). Column 1: Core Column 2: Depth (cm) Column 3: Age (kyr BP) Column 4: UK'37 Column 5: SST (°C) Core Depth Age UK'37 SST TR163-19P 1 0.99 0.893 25.12 TR163-19P 2.5 1.37 0.897 25.24 TR163-19P 4.5 1.86 0.915 25.76 TR163-19P 6.5 2.36 0.9 25.32 TR163-19P 9.5 3.1 0.9 25.32 TR163-19P 11 3.5 0.891 25.06 TR163-19P 12.5 3.89 0.883 24.82 TR163-19P 14 4.28 0.895 25.18 TR163-19P 19 5.6 0.888 24.97 TR163-19P 24 6.65 0.887 24.94 TR163-19P 29 8.07 0.889 25 TR163-19P 34 9.5 0.882 24.79 TR163-19P 39 10.88 0.877 24.65 TR163-19P 44 12.21 0.851 23.88 TR163-19P 49 13.39 0.855 24 TR163-19P 54 14.57 0.86 24.15 TR163-19P 59 15.9 0.848 23.79 TR163-19P 64 17.29 0.854 23.97 TR163-19P 69 18.71 0.856 24.03 TR163-19P 74 20.54 0.858 24.09 TR163-19P 79 22.76 0.856 24.03 TR163-19P 84 24.6 0.854 23.97 TR163-19P 89 26.09 0.841 23.59 TR163-19P 94 27.5 0.854 23.97 TR163-19P 99 28.83 0.845 23.71 4. Core TR163-22P UK'37 and UK-based SST. Age model from Lea et al. (2006). Column 1: Core Column 2: Depth (cm) Column 3: Age (kyr BP) Column 4: UK'37 Column 5: SST (°C) Core Depth Age UK'37 SST TR163-22P 1.5 0.98 0.858 24.1 TR163-22P 5 1.43 0.869 24.4 TR163-22P 10 2.08 0.869 24.4 TR163-22P 19.5 3.32 0.841 23.6 TR163-22P 24 3.9 0.841 23.6 TR163-22P 29.5 4.66 0.835 23.4 TR163-22P 34 5.2 0.848 23.8 TR163-22P 39.5 5.96 0.841 23.6 TR163-22P 44 6.5 0.848 23.8 TR163-22P 48.5 7.13 0.845 23.7 TR163-22P 54 7.8 0.845 23.7 TR163-22P 60.5 8.61 0.838 23.5 TR163-22P 63 8.96 0.841 23.6 TR163-22P 69.5 9.76 0.841 23.6 TR163-22P 73.5 10.24 0.841 23.6 TR163-22P 78.5 10.84 0.828 23.2 TR163-22P 84 11.6 0.804 22.5 TR163-22P 88 12.08 0.787 22 TR163-22P 94 12.7 0.797 22.3 TR163-22P 99.5 13.15 0.801 22.4 TR163-22P 104 13.6 0.794 22.2 TR163-22P 108.5 13.96 0.801 22.4 TR163-22P 114 14.5 0.763 21.3 TR163-22P 119 15 0.784 21.9 TR163-22P 124 15.4 0.784 21.9 TR163-22P 127.5 15.72 0.787 22 TR163-22P 131.5 16.08 0.78 21.8 TR163-22P 137.5 16.65 0.777 21.7 TR163-22P 141.5 17.05 0.773 21.6 TR163-22P 147.5 17.65 0.79 22.1 TR163-22P 152 18.04 0.79 22.1 TR163-22P 157.5 18.55 0.784 21.9 TR163-22P 162 18.94 0.797 22.3 TR163-22P 166.5 19.4 0.804 22.5 TR163-22P 171.5 19.93 0.79 22.1 TR163-22P 175.5 20.29 0.79 22.1 TR163-22P 181 20.76 0.79 22.1 TR163-22P 187.5 21.42 0.797 22.3 TR163-22P 193 21.92 0.797 22.3 TR163-22P 197.5 22.35 0.811 22.7 TR163-22P 202 22.74 0.807 22.6 TR163-22P 206.5 23.15 0.801 22.4 TR163-22P 212 23.67 0.777 21.7 TR163-22P 216.5 24.08 0.79 22.1 TR163-22P 223 24.7 0.801 22.4 TR163-22P 227.5 25.15 0.794 22.2 TR163-22P 232 25.57 0.794 22.2 TR163-22P 235.5 25.89 0.79 22.1 TR163-22P 241 26.36 0.787 22 TR163-22P 246.5 26.85 0.777 21.7 TR163-22P 253 27.5 0.794 22.2 TR163-22P 261 28.52 0.804 22.5 TR163-22P 266 29.07 0.804 22.5 TR163-22P 272 29.76 0.801 22.4 5. Core TR163-31P UK'37 and UK-based SST. Age model from Martin et al. (2002). Column 1: Core Column 2: Depth (cm) Column 3: Age (kyr BP) Column 4: UK'37 Column 5: SST (°C) Core Depth Age UK'37 SST TR163-31P 3 5.44 0.792 22.13 TR163-31P 6 5.84 0.807 22.58 TR163-31P 9 6.24 0.809 22.65 TR163-31P 12 6.65 0.806 22.56 TR163-31P 15 7.05 0.792 22.16 TR163-31P 16.5 7.26 0.804 22.49 TR163-31P 20 7.73 0.781 21.82 TR163-31P 24 8.37 0.82 22.98 TR163-31P 27 8.93 0.808 22.61 TR163-31P 30 9.48 0.803 22.48 TR163-31P 33 10.03 0.802 22.43 TR163-31P 36 10.59 0.783 21.91 TR163-31P 39 11.14 0.782 21.76 TR163-31P 42 11.71 0.763 21.3 TR163-31P 45 12.3 0.78 21.78 TR163-31P 48 12.9 0.76 21.2 TR163-31P 54 13.88 0.769 21.9 TR163-31P 57 14.15 0.761 21.23 TR163-31P 60 14.42 0.763 21.31 TR163-31P 63 14.7 0.758 21.13 TR163-31P 66 15 0.753 20.99 TR163-31P 69 15.3 0.763 21.3 TR163-31P 74 15.8 0.759 21.18 TR163-31P 77 16.1 0.772 21.56 TR163-31P 80 16.4 0.772 21.55 TR163-31P 83 16.68 0.75 20.91 TR163-31P 89 17.26 0.779 21.78 TR163-31P 92 17.55 0.738 20.57 TR163-31P 95 17.84 0.729 20.3 TR163-31P 101 18.42 0.74 20.62 TR163-31P 104 18.7 0.735 20.47 TR163-31P 107 18.98 0.765 21.35 TR163-31P 110 19.25 0.75 20.92 TR163-31P 116 19.8 0.743 20.7 TR163-31P 122 20.26 0.735 20.47 TR163-31P 128 20.64 0.754 21.03 TR163-31P 134 20.97 0.739 20.58 TR163-31P 140 21.19 0.73 20.33 TR163-31P 146 21.4 0.754 21.02 TR163-31P 152 21.62 0.759 21.17 TR163-31P 158 21.83 0.738 20.54 TR163-31P 164 22.04 0.749 20.89 TR163-31P 170 22.26 0.749 20.88 TR163-31P 188 22.9 0.745 20.75 TR163-31P 203 23.43 0.752 20.97 TR163-31P 233 24.7 0.746 20.78