Congo River Basin 25KYr MBT/CBT Data and Temperature Reconstruction ----------------------------------------------------------------------- World Data Center for Paleoclimatology, Boulder and NOAA Paleoclimatology Program ----------------------------------------------------------------------- NOTE: PLEASE CITE ORIGINAL REFERENCE WHEN USING THIS DATA!!!!! NAME OF DATA SET: Congo River Basin 25KYr MBT/CBT Data and Temperature Reconstruction LAST UPDATE: 5/2008 (Original receipt by WDC Paleo) CONTRIBUTOR: Johan W.H. Weijers, Royal Netherlands Institute for Sea Research. IGBP PAGES/WDCA CONTRIBUTION SERIES NUMBER: 2008-050 WDC PALEO CONTRIBUTION SERIES CITATION: Weijers, J. W. H., et al. 2008. Congo River Basin 25KYr MBT/CBT Data and Temperature Reconstruction. IGBP PAGES/World Data Center for Paleoclimatology Data Contribution Series # 2008-050. NOAA/NCDC Paleoclimatology Program, Boulder CO, USA. ORIGINAL REFERENCE: Weijers, J.W.H., E. Schefuss, S. Schouten, J.S. Sinninghe Damsté. 2007. Coupled Thermal and Hydrological Evolution of Tropical Africa over the Last Deglaciation. Science, Vol.315, p.1701-1704. doi: 10.1126/science.1138131 ABSTRACT: We analyzed the distribution of branched tetraether membrane lipids derived from soil bacteria in a marine sediment record that was recovered close to the Congo River outflow, and the results enabled us to reconstruct large-scale continental temperature changes in tropical Africa that span the past 25,000 years. Tropical African temperatures gradually increased from ~21° to 25°C over the last deglaciation, which is a larger warming than estimated for the tropical Atlantic Ocean. A direct comparison with sea-surface temperature estimates from the same core revealed that the land-sea temperature difference was, through the thermal pressure gradient, an important control on central African precipitation patterns. GEOGRAPHIC REGION: Congo River Basin/Congo Fan, tropical central Africa PERIOD OF RECORD: 25 KYrBP - present FUNDING SOURCES: Earth and Life Sciences Council of the Netherlands Organization for Scientific Research and the Deutsche Forschungsgemeinschaft. DESCRIPTION: 25 ky MBT/CBT record for the Congo River Basin (central tropical Africa) obtained from marine core GeoB 6518-1 situated in the Congo deep sea fan. Annual mean air temperature and soil pH estimates have been obtained from branched tetraether membrane lipids derived from soil bacteria and analysed with high performance liquid chromatography / mass spectrometry (HPLC/MS). Core Location: GeoB 6518-1: 05°35.3'S, 11°13.3'E, 962m water depth (Congo Fan). Age calibration of core: Dating of core GeoB 6518-1 was carried out by means of fifteen 14C-AMS dates on mixed planktonic foraminifera fractions containing Globigerinoides ruber (white), Globigerinoides sacculifer and Orbulina universa. Radiocarbon ages were converted to calendar ages using the program CALIB 4.4 (using the marine calibration and applying a reservoir effect of 400 years) and were linearly interpolated to provide the core chronology. Uncertainties: The pH calibration range is from 3.3 to 8.2 and the temperature calibration range is from -6.7 to 27.0°C, which covers the entire range of pH and temperatures reconstructed from our core. The analytical reproducibility based on pooled standard deviations of duplicate measurements of samples is =< 0.01 units for the MBT index and ± 0.01 units for the CBT ratio, or ± 0.02 pH units and ± 0.2°C in the temperature estimates. DATA: Column 1: Depth Column 2: Age (kyr) Column 3: Methylation index of Branched Tetraethers (MBT) Column 4: Cyclization ratio of Branched Tetraethers (CBT) Column 5: Soil pH Column 6: Mean Air Temperature of the Congo River basin (°C) Depth Age MBT CBT Soil pH MAT 3 0.03 0.841 1.173 5.603 24.62 8 0.09 0.832 1.152 5.658 24.39 13 0.15 0.84 1.177 5.592 24.56 18 0.21 0.838 1.173 5.604 24.48 23 0.27 0.842 1.174 5.601 24.66 28 0.33 0.829 1.161 5.634 24.14 33 0.39 0.824 1.139 5.691 24.1 38 0.45 0.832 1.148 5.668 24.4 43 0.51 0.824 1.148 5.668 24.02 48 0.57 0.831 1.135 5.702 24.46 53 0.63 0.825 1.137 5.695 24.15 58 0.69 0.843 1.147 5.669 24.97 63 1.05 0.844 1.165 5.624 24.82 68 1.4 0.844 1.154 5.651 24.93 73 1.76 0.845 1.162 5.632 24.94 78 2.11 0.842 1.158 5.641 24.81 83 2.47 0.848 1.164 5.627 25.03 88 2.83 0.846 1.179 5.588 24.81 93 3.18 0.843 1.169 5.613 24.74 98 3.54 0.847 1.178 5.59 24.86 103 3.89 0.853 1.198 5.538 25 108 4.25 0.845 1.164 5.627 24.92 113 4.45 0.846 1.194 5.549 24.66 118 4.66 0.841 1.177 5.593 24.61 123 4.87 0.856 1.229 5.457 24.87 128 5.08 0.853 1.208 5.511 24.88 133 5.28 0.855 1.228 5.46 24.82 138 5.49 0.857 1.213 5.499 25.03 143 5.7 0.849 1.22 5.481 24.56 148 5.9 0.851 1.222 5.476 24.64 153 6.11 0.851 1.207 5.514 24.8 158 6.32 0.85 1.206 5.516 24.75 163 6.4 0.846 1.21 5.507 24.5 168 6.48 0.852 1.22 5.48 24.72 173 6.56 0.851 1.221 5.477 24.65 178 6.64 0.848 1.226 5.465 24.46 183 6.72 0.847 1.249 5.404 24.23 188 6.8 0.852 1.236 5.44 24.6 193 6.88 0.848 1.24 5.428 24.35 198 6.96 0.849 1.227 5.462 24.49 203 7.04 0.841 1.202 5.527 24.36 208 7.13 0.842 1.207 5.513 24.33 213 7.27 0.846 1.207 5.514 24.55 218 7.41 0.845 1.237 5.437 24.23 223 7.55 0.842 1.23 5.456 24.12 228 7.69 0.852 1.25 5.402 24.46 233 7.84 0.851 1.236 5.438 24.52 238 7.98 0.845 1.237 5.436 24.22 243 8.12 0.842 1.237 5.437 24.09 248 8.26 0.844 1.254 5.391 24.01 253 8.41 0.852 1.243 5.42 24.49 258 8.51 0.849 1.254 5.393 24.24 263 8.56 0.847 1.263 5.369 24.07 268 8.62 0.854 1.261 5.375 24.47 273 8.68 0.853 1.265 5.363 24.36 278 8.74 0.849 1.257 5.383 24.24 283 8.79 0.849 1.24 5.429 24.41 288 8.85 0.847 1.26 5.377 24.13 293 8.91 0.858 1.283 5.316 24.42 298 8.96 0.85 1.25 5.404 24.37 303 9.02 0.844 1.244 5.418 24.13 308 9.08 0.836 1.255 5.39 23.64 313 9.15 0.841 1.244 5.418 23.95 318 9.22 0.838 1.242 5.422 23.83 323 9.28 0.834 1.236 5.438 23.69 328 9.35 0.833 1.242 5.423 23.57 333 9.41 0.833 1.217 5.488 23.84 338 9.48 0.83 1.219 5.483 23.67 343 9.55 0.827 1.208 5.511 23.63 348 9.61 0.824 1.216 5.49 23.4 353 9.68 0.833 1.211 5.505 23.88 358 9.8 0.824 1.23 5.455 23.25 363 9.97 0.823 1.236 5.438 23.14 368 10.14 0.831 1.235 5.441 23.54 373 10.32 0.835 1.237 5.437 23.73 378 10.49 0.827 1.219 5.482 23.51 383 10.66 0.821 1.185 5.571 23.52 388 10.84 0.819 1.203 5.525 23.26 393 11.01 0.814 1.185 5.571 23.16 398 11.18 0.801 1.133 5.707 23.02 403 11.36 0.779 1.053 5.915 22.65 408 11.52 0.782 1.065 5.882 22.71 413 11.69 0.787 1.101 5.79 22.62 418 11.85 0.787 1.087 5.826 22.74 423 12.02 0.788 1.099 5.795 22.68 428 12.18 0.79 1.123 5.733 22.57 433 12.34 0.779 1.09 5.818 22.34 438 12.51 0.786 1.102 5.786 22.56 443 12.67 0.781 1.079 5.847 22.53 448 12.83 0.794 1.127 5.722 22.72 453 13 0.799 1.158 5.643 22.67 458 13.14 0.796 1.152 5.658 22.61 463 13.25 0.795 1.14 5.689 22.64 468 13.37 0.793 1.134 5.705 22.64 473 13.49 0.787 1.129 5.718 22.35 478 13.6 0.79 1.167 5.618 22.15 483 13.72 0.785 1.152 5.656 22.03 488 13.83 0.79 1.142 5.683 22.4 493 13.95 0.783 1.15 5.663 21.96 498 14.06 0.784 1.155 5.649 21.98 503 14.18 0.786 1.162 5.632 22.01 508 14.39 0.78 1.117 5.749 22.13 513 14.69 0.78 1.139 5.69 21.91 518 14.99 0.773 1.127 5.721 21.67 523 15.29 0.767 1.117 5.747 21.49 528 15.59 0.74 1.068 5.875 20.59 533 15.89 0.732 1.039 5.95 20.49 538 16.2 0.739 1.042 5.942 20.82 543 16.5 0.733 1.061 5.894 20.32 548 16.8 0.726 1.045 5.936 20.15 553 17.1 0.727 1.06 5.896 20.05 558 17.7 0.751 1.086 5.829 21.01 563 18.6 0.757 1.099 5.796 21.19 568 19.5 0.756 1.097 5.8 21.12 573 20.4 0.747 1.073 5.863 20.89 578 21.3 0.758 1.093 5.811 21.25 583 22.2 0.739 1.073 5.862 20.51 588 23.1 0.748 1.077 5.853 20.91 593 23.99 0.748 1.065 5.882 21.02 598 24.89 0.747 1.083 5.835 20.82 603 25.79 0.758 1.102 5.786 21.17