Reconstructed 60 Million Year Atmospheric Carbon Dioxide Concentration Data ----------------------------------------------------------------------- World Data Center for Paleoclimatology, Boulder and NOAA Paleoclimatology Program ----------------------------------------------------------------------- NOTE: PLEASE CITE CONTRIBUTORS WHEN USING THIS DATA!!!!! NAME OF DATA SET: Reconstructed 60 Million Year Atmospheric Carbon Dioxide Concentration Data LAST UPDATE: 10/2003 (Original Receipt by WDC Paleo) CONTRIBUTOR: Paul Pearson, University of Bristol (now at Cardiff University) IGBP PAGES/WDCA CONTRIBUTION SERIES NUMBER: 2003-069 SUGGESTED DATA CITATION: Pearson, P.N. and M.R. Palmer, 2003, Reconstructed 60 Million Year Atmospheric Carbon Dioxide Concentration Data, IGBP PAGES/World Data Center for Paleoclimatology Data Contribution Series # 2003-069. NOAA/NGDC Paleoclimatology Program, Boulder CO, USA. ORIGINAL REFERENCE: Pearson, P.N. and M.R. Palmer, 2000, Atmospheric carbon dioxide concentrations over the past 60 million years, Nature, v. 406, pp. 695, 17 August 2000. GEOGRAPHIC REGION: Global PERIOD OF RECORD: 60 - 0.08 MMYrBP DESCRIPTION: Planktonic boron isotope data, estimated sea-surface pH, and reconstructed atmospheric CO2 concentrations. Boron isotope measurements on mixed-layer foraminifera from 32 sediment samples in the tropical Pacific. Samples are from Ocean Drilling Program sites 865, 871, and 872. ODP865: 18.44N -179.55W 1517m depth. ODP871: 5.557N 172.345E 1254m depth. ODP872: 10.097N 162.867E 1082m depth. ABSTRACT: Knowledge of the evolution of atmospheric carbon dioxide concentrations throughout the Earth's history is important for a reconstruction of the links between climate and radiative forcing of the Earth's surface temperatures. Although atmospheric carbon dioxide concentrations in the early Cenozoic era (about 60Myr ago) are widely believed to have been higher than at present, there is disagreement regarding the exact carbon dioxide levels, the timing of the decline and the mechanisms that are most important for the control of CO2 concentrations over geological timescales. Here we use the boron-isotope ratios of ancient planktonic foraminifer shells to estimate the pH of surface-layer sea water throughout the past 60 million years, which can be used to reconstruct atmospheric CO2 concentrations. We estimate CO2 concentrations of more than 2,000 p.p.m. for the late Palaeocene and earliest Eocene periods (from about 60 to 52 Myr ago), and find an erratic decline between 55 and 40 Myr ago that may have been caused by reduced CO2 outgassing from ocean ridges, volcanoes and metamorphic belts and increased carbon burial. Since the early Miocene (about 24Myr ago), atmospheric CO2 concentrations appear to have remained below 500 p.p.m. and were more stable than before, although transient intervals of CO2 reduction may have occurred during periods of rapid cooling approximately 15 and 3 Myr ago. DATA: Column 1: Core Column 2: Sample ID Column 3: Depth Column 4: Species Column 5: Size Range Column 6: Age, millions of years before present Column 7: Top Datum, age error 1 Column 8: Bottom Datum, age error 2 Column 9: d11B of Calcium Carbonate, per mill, relative to standard NBS SRM 951 Column 10: d11B analytical error (2 sigma) Column 11: pH Column 12: pH error 1 Column 13: pH error 2 Column 14: pCO2 Column 15: pCO2 error 1 Column 16: pCO2 error 2 Column 17: alkalinity, Column 18: alk. Error 1 Column 19: alk. Error 2 Core Sample Depth Species Size range Age Age- Age+ d11B +/- pH pHerr+ pHerr- pCO2 CO2err+ CO2err- alk alkerr+ AlkErr- 871A 1H/1 124-126 Various 0.085 0.06 0.11 24.9 0.4 8.096 8.143 8.047 341 427 284 2335 2500 2225 871A 2H/2 59-61 G. trilobus 500-600 0.98 0.47 1.37 25.1 0.1 8.12 8.131 8.108 311 328 296 2260 2300 2225 871A 2H/6 59-61 G. trilobus 500-600 1.49 1.45 1.68 25.2 0.3 8.131 8.165 8.096 295 342 255 2220 2305 2150 871A 3H/2 123-125 Various 3 2.9 3.1 25.9 0.4 8.209 8.251 8.165 208 253 173 2010 2125 1900 872C 3H/2 59-61 G. trilobus 500-600 3.31 3.1 3.5 25.5 0.1 8.173 8.184 8.162 248 263 239 2110 2135 2095 872C 3H/5 118-120 G. trilobus 500-600 3.87 3.8 3.9 25.1 0.2 8.142 8.164 8.118 281 310 255 2180 2245 2120 871A 3H/5 60-62 G. trilobus 500-600 6 5.8 7.1 24.9 0.1 8.154 8.166 8.144 268 277 260 2150 2170 2135 871A 3H/5 123-125 Various 6.2 5.8 7.1 24.5 0.3 8.116 8.151 8.08 305 351 265 2225 2295 2160 872C 5H/2 14-16 G. trilobus 500-600 9.02 7.1 10.2 25 0.1 8.198 8.209 8.187 212 221 204 2000 2020 1985 872C 5H/6 59-61 G. trilobus 500-600 10.39 10.2 10.4 24.5 0.2 8.177 8.199 8.155 236 259 215 2080 2130 2035 872C 6H/5 20-22 G. trilobus 500-600 11.4 11.3 11.5 24.4 0.4 8.188 8.231 8.144 226 272 187 2050 2150 1960 871A 4H/5 59-61 Various 11.81 11.5 12.6 24.1 0.3 8.164 8.198 8.131 260 292 238 2150 2265 2020 871A 6H/6 60-62 G. trilobus 300-425 13.06 12.6 13.1 24.4 0.4 8.198 8.24 8.154 222 268 183 2075 2135 2030 871A 7H/2 124-126 G. trilobus 300-425 14.73 14.6 14.9 25.5 0.4 8.311 8.35 8.271 137 170 112 1830 1910 1760 871A 7H/5 59-61 G. trilobus 300-425 14.96 14.9 15.2 25 0.2 8.261 8.281 8.24 170 182 159 1940 1950 1930 871A 8H/2 59-63 Various 16.23 16.2 16.3 23.7 0.4 8.12 8.165 8.072 303 365 247 2210 2285 2140 872C 11H/1 20-22 G. trilobus 300-425 16.7 16.6 19 24.3 0.3 8.182 8.214 8.148 236 270 208 2075 2115 2040 872C 11H/6 20-22 G. trilobus 300-425 18.38 16.6 19 24.6 0.1 8.204 8.215 8.194 217 223 211 2035 2055 2020 872C 12H/2 78-80 G. trilobus 300-425 19.85 19 21.8 24.7 0.4 8.201 8.243 8.157 217 261 178 2035 2110 1970 872C 13H/3 20-22 G. trilobus 300-425 21.7 19 21.8 24.7 0.4 8.194 8.237 8.151 226 267 189 2050 2125 1980 872C 13H/5 20-22 G. trilobus 300-425 23 22.8 23.2 24.3 0.1 8.14 8.152 8.129 278 293 265 2150 2175 2125 872C 14H/4 20-22 G. trilobus 300-425 23.51 23.2 23.7 23.5 0.2 8.036 8.061 8.009 435 487 392 2500 2575 2430 865C 5H/1 110-112 A. topilensis 300-425 40.12 40.1 40.5 23 0.5 7.802 7.886 7.705 1004 1427 729 2950 3250 2700 865C 6H/2 65-67 Various 42.52 40.5 43.6 25 0.5 8.072 8.131 8.008 342 443 264 2160 2330 2010 865C 7H/1 110-112 A. topilensis 300-425 44.26 43.6 45.8 24.1 0.2 7.953 7.981 7.924 562 632 501 2500 2600 2420 865C 7H/3 110-112 A. praetopilensis 300-425 45.69 43.6 45.8 23.1 0.6 7.791 7.893 7.67 1041 1610 708 2980 3350 2675 865C 8H/3 110-112 A. praetopilensis 300-425 46.07 45.8 46.1 22 0.1 7.544 7.571 7.515 2446 2678 2250 3660 3750 3580 865C 8H/5 110-112 A. praetopilensis 300-425 46.97 46.1 49 24.4 0.4 7.994 8.047 7.938 471 585 374 2350 2510 2200 865C 9H/5 110-112 A. praetopilensis 500-600 50.33 49 50.4 23.4 0.1 7.844 7.861 7.827 844 902 792 2765 2820 2720 865C 10H/1 110-112 M. caucasica 500-600 51.02 50.8 52.3 23.9 0.5 7.923 7.995 7.845 619 833 461 2530 2760 2325 865C 10H/5 100-102 M. caucasica 425-500 52.22 50.8 52.3 21.6 0.2 7.415 7.485 7.34 3515 4620 2920 3900 4200 3775 865C 11H/1 110-112 M. marginodentata 425-500 53.24 52.3 54 22.3 0.4 7.624 7.714 7.516 1865 2640 1361 3330 3700 3175 865C 12H/5 110-112 M. velascoensis s. l425-500 55.84 54.7 55.9 21.8 0.3 7.485 7.573 7.38 2930 4092 2221 3775 4100 3600 865C 14H/3 110-112 M. velascoensis s. l300-425 57.12 57.1 57.5 22 0.4 7.544 7.647 7.415 2426 3708 1736 3630 4050 3400 865C 15H/5 110-112 M. velascoensis s. l300-425 59.88 59.2 60 21.6 0.2 7.415 7.485 7.34 3560 4630 2930 3950 4250 3825