Table 4.
Summary table of U-Th disequilibrium ages obtained for the three H. naledi teeth (samples 1767, 1788 and 1810) and the baboon tooth (sample 1841) from the Dinaledi Chamber obtained by SCU-UoW. No age calculations were carried out for U concentrations of ≤0.5 ppm or U/Th ≤250 (indicated in red and underlined). Mean values in this table only incorporate values from which meaningful ages could be calculated (indicated in black), however all values (i.e., red and black) were averaged to obtain the relevant mean values reported in Table 4. All uncertainties are given as 2σ.
| Sample1767 | U (ppm) | U/Th | 230Th/238U | 2σ | 234U/238U | 2σ | Age (ka) | 2s (ka) | (234U/238U)i | 2σ |
|---|---|---|---|---|---|---|---|---|---|---|
| 1767-1 D | 7.22 | 685 | 2.167 | 0.024 | 6.259 | 0.009 | 43.5 | 1.1 | 6.949 | 0.026 |
| 1767-2 D | 7.75 | 996 | 2.261 | 0.023 | 6.282 | 0.010 | 45.5 | 1.1 | 7.009 | 0.030 |
| 1767-3 D | 8.03 | 196 | 2.225 | 0.825 | 6.276 | 0.012 | – | – | – | – |
| 1767-4 D | 8.55 | 951 | 2.209 | 0.031 | 6.301 | 0.009 | 44.1 | 1.4 | 7.007 | 0.030 |
| 1767-5* E | 3.69 | 1238 | 2.259 | 0.031 | 6.197 | 0.055 | 46.2 | 1.8 | 6.924 | 0.126 |
| 1767-6* E | 1.76 | 108 | 2.239 | 1.133 | 6.165 | 0.038 | – | – | – | – |
| 1767-7* E | 2.15 | 109 | 2.337 | 0.947 | 6.231 | 0.024 | – | – | – | – |
| 1767-8* E | 2.46 | 518 | 2.276 | 0.021 | 6.253 | 0.019 | 46.1 | 1.1 | 6.986 | 0.048 |
| Mean: | ||||||||||
| 1767 D | 7.84 | 877 | 2.212 | 0.026 | 6.281 | 0.009 | 44.5 | 1.2 | 6.988 | 0.029 |
| 1767 E | 3.08 | 878 | 2.268 | 0.026 | 6.225 | 0.037 | 46.2 | 1.4 | 6.955 | 0.087 |
| Sample1788 | U (ppm) | U/Th | 230Th/238U | 2σ | 234U/238U | 2σ | Age (ka) | 2s (ka) | (234U/238U)i | 2σ |
| 1788-1 D | 6.67 | 390 | 2.967 | 0.026 | 6.423 | 0.011 | 61.4 | 1.5 | 7.453 | 0.054 |
| 1788-2 D | 7.08 | 176 | 3.370 | 0.833 | 6.441 | 0.010 | – | – | – | – |
| 1788-3 D | 7.17 | 60 | 3.206 | 3.126 | 6.394 | 0.049 | – | – | – | – |
| 1788-4 D | 7.45 | 1391 | 3.313 | 0.023 | 6.445 | 0.010 | 70.3 | 1.4 | 7.645 | 0.056 |
| 1788-5 D | 5.52 | 4423 | 3.269 | 0.023 | 6.349 | 0.010 | 70.4 | 1.4 | 7.531 | 0.052 |
| 1788-6 D | 5.07 | 4090 | 3.416 | 0.014 | 6.378 | 0.014 | 74.1 | 1.1 | 7.634 | 0.054 |
| 1788-7 D | 5.39 | 4729 | 3.385 | 0.020 | 6.400 | 0.014 | 72.9 | 1.4 | 7.640 | 0.054 |
| 1788-8 D | 5.93 | 3209 | 3.427 | 0.015 | 6.393 | 0.013 | 74.2 | 1.1 | 7.654 | 0.054 |
| 1788-9 D | 5.24 | 4329 | 3.449 | 0.014 | 6.413 | 0.014 | 74.5 | 1.0 | 7.685 | 0.052 |
| 1788-10 D | 4.89 | 3161 | 3.390 | 0.010 | 6.403 | 0.011 | 73.0 | 0.9 | 7.645 | 0.052 |
| 1788-11 D | 4.8 | 2556 | 3.394 | 0.014 | 6.416 | 0.014 | 72.9 | 1.0 | 7.659 | 0.052 |
| 1788-12 D | 5.48 | 1606 | 3.356 | 0.017 | 6.384 | 0.014 | 72.3 | 1.1 | 7.609 | 0.052 |
| 1788-13 D | 5.04 | 838 | 3.317 | 0.025 | 6.420 | 0.014 | 70.7 | 1.5 | 7.623 | 0.058 |
| 1788-14 D | 5.69 | 93 | 3.281 | 2.426 | 6.408 | 0.013 | – | – | – | – |
| 1788-15 D | 5.03 | 72 | 3.315 | 3.731 | 6.427 | 0.014 | – | – | – | – |
| 1788-16 E | 0.13 | 3 | 1.786 | 18.149 | 3.834 | 0.267 | – | – | – | – |
| 1788-17 E | 0.68 | 25 | 0.752 | 9.149 | 6.248 | 0.273 | – | – | – | – |
| 1788-18 E | 0.4 | 16 | 0.801 | 13.053 | 6.236 | 0.050 | – | – | – | – |
| 1788-19 E | 0.08 | 3 | 1.783 | 36.231 | 4.301 | 0.288 | – | – | – | – |
| 1788-20 E | 1.02 | 306 | 2.990 | 0.117 | 5.541 | 0.154 | 75.1 | 9.3 | 6.617 | 0.394 |
| 1788-21* E | 0.33 | 50 | 2.041 | 27.135 | 5.793 | 0.141 | – | – | – | – |
| 1788-22* E | 0.12 | 30 | 1.513 | 24.801 | 5.975 | 0.098 | – | – | – | – |
| 1788-23* E | 0.25 | 34 | 1.368 | 17.071 | 5.988 | 0.079 | – | – | – | – |
| 1788-24* E | 0.36 | 90 | 1.237 | 13.555 | 6.167 | 0.055 | – | – | – | – |
| 1788-25* E | 0.41 | 107 | 1.084 | 8.672 | 6.206 | 0.033 | – | – | – | – |
| 1788-26* E | 0.48 | 102 | 1.302 | 11.333 | 6.384 | 0.081 | – | – | – | – |
| 1788-27* E | 0.49 | 165 | 0.686 | 7.733 | 6.367 | 0.037 | – | – | – | – |
| 1788-28* E | 0.31 | 167 | 1.615 | 6.975 | 5.602 | 0.246 | – | – | – | – |
| 1788-29* E | 0.44 | 6 | 2.311 | 11.898 | 5.576 | 0.306 | – | – | – | – |
| 1788-30 E | 0.44 | 62 | 0.988 | 5.310 | 6.089 | 0.075 | – | – | – | – |
| 1788-31 E | 0.29 | 8 | 1.066 | 19.256 | 6.151 | 0.056 | – | – | – | – |
| 1788-32 E | 0.23 | 95 | 0.994 | 17.451 | 6.352 | 0.064 | – | – | – | – |
| 1788-33 E | 0.41 | 6 | 1.103 | 21.651 | 6.344 | 0.049 | – | – | – | – |
| 1788-34 E | 0.28 | 51 | 1.340 | 11.450 | 6.382 | 0.061 | – | – | – | – |
| 1788-35 E | 0.35 | 4 | 1.286 | 21.088 | 6.321 | 0.062 | – | – | – | – |
| 1788-36 E | 0.4 | 115 | 1.216 | 12.896 | 6.372 | 0.041 | – | – | – | – |
| 1788-37 E | 0.3 | 61 | 1.106 | 17.059 | 6.313 | 0.073 | – | – | – | – |
| 1788-38 E | 0.54 | 279 | 2.810 | 0.237 | 6.300 | 0.064 | 58.9 | 12.2 | 7.262 | 0.270 |
| Mean: | ||||||||||
| 1788 D | 5.59 | 2793 | 3.335 | 0.018 | 6.402 | 0.013 | 71.5 | 1.2 | 7.616 | 0.054 |
| 1788 E | 0.78 | 293 | 2.900 | 0.177 | 5.920 | 0.109 | 67.0 | 10.8 | 6.936 | 0.332 |
| Sample1810 | U (ppm) | U/Th | 230Th/238U | 2σ | 234U/238U | 2σ | Age (ka) | 2s (ka) | (234U/238U)i | 2σ |
| 1810-1 D | 7.07 | 348 | 3.231 | 0.021 | 5.814 | 0.017 | 77.9 | 1.6 | 7.003 | 0.056 |
| 1810-2 D | 8.29 | 411 | 3.112 | 0.030 | 5.863 | 0.010 | 73.4 | 2.1 | 6.986 | 0.062 |
| 1810-3 D | 8.88 | 979 | 3.106 | 0.027 | 5.929 | 0.010 | 72.1 | 1.8 | 7.046 | 0.060 |
| 1810-4 D | 9.19 | 833 | 3.049 | 0.044 | 5.993 | 0.011 | 69.4 | 2.6 | 7.079 | 0.066 |
| 1810-5 D | 9.17 | 508 | 2.937 | 0.047 | 5.990 | 0.007 | 66.2 | 2.8 | 7.020 | 0.066 |
| 1810-6 D | 9.12 | 55 | 3.143 | 6.919 | 5.981 | 0.012 | – | – | – | – |
| 1810-7 D | 7.95 | 432 | 3.099 | 0.018 | 5.977 | 0.013 | 71.1 | 1.3 | 7.089 | 0.054 |
| 1810-8 D | 8.84 | 489 | 2.986 | 0.074 | 6.035 | 0.060 | 67 | 4.1 | 7.088 | 0.084 |
| 1810-9 D | 9.39 | 15905 | 3.122 | 0.013 | 5.870 | 0.006 | 73.6 | 1.1 | 6.999 | 0.052 |
| 1810-10 D | 9.78 | 7839 | 3.165 | 0.017 | 5.873 | 0.011 | 74.8 | 1.3 | 7.024 | 0.054 |
| 1810-11 D | 9.03 | 7242 | 3.174 | 0.030 | 5.888 | 0.015 | 74.8 | 2.0 | 7.043 | 0.058 |
| 1810-12 D | 9.53 | 9626 | 3.157 | 0.019 | 5.889 | 0.009 | 74.3 | 1.4 | 7.036 | 0.054 |
| 1810-13 D | 10.19 | 10240 | 3.094 | 0.018 | 5.904 | 0.008 | 72.2 | 1.3 | 7.016 | 0.052 |
| 1810-14 D | 10.64 | 14463 | 3.155 | 0.030 | 5.958 | 0.010 | 73.1 | 1.9 | 7.099 | 0.058 |
| 1810-15 E | 0.005 | 1 | −0.384 | 146.036 | 1.965 | 0.186 | – | – | – | – |
| 1810-16 E | 0.002 | 2 | −1.060 | 48.168 | 1.014 | 0.108 | – | – | – | – |
| 1810-17 E | 0.004 | 1 | 5.403 | 17.573 | 2.357 | 0.194 | – | – | – | – |
| 1810-18 E | 0.24 | 55 | 3.195 | 9.109 | 4.054 | 0.062 | – | – | – | – |
| 1810-19 E | 0.54 | 426 | 4.009 | 0.186 | 5.054 | 0.109 | 130.8 | 21.8 | 6.872 | 0.466 |
| 1810-20 E | 0.85 | 328 | 3.625 | 0.119 | 4.287 | 0.137 | 146.8 | 22.7 | 5.984 | 0.524 |
| 1810-21 E | 0.41 | 48 | 5.009 | 4.474 | 4.494 | 0.186 | – | – | – | – |
| 1810-22 E | 0.15 | 7 | 7.690 | 8.225 | 4.349 | 0.351 | – | – | – | – |
| 1810-23 E | 0.03 | 2 | 9.912 | 1.843 | 5.153 | 0.599 | – | – | – | – |
| 1810-24 E | 0.01 | 0 | 0.661 | 166.056 | 1.877 | 0.144 | – | – | – | – |
| 1810-25 E | 0.02 | 2 | 7.408 | 9.386 | 4.964 | 0.557 | – | – | – | – |
| 1810-26* E | 0.73 | 3 | 3.762 | 4.100 | 4.735 | 0.100 | – | – | – | – |
| 1810-27* E | 0.14 | 3 | 5.271 | 4.510 | 4.255 | 0.112 | – | – | – | – |
| 1810-28* E | 0.18 | 5 | 3.541 | 8.079 | 4.562 | 0.081 | – | – | – | – |
| 1810-29* E | 0.25 | 9 | 3.511 | 7.095 | 4.562 | 0.058 | – | – | – | – |
| 1810-30* E | 0.21 | 3 | 4.027 | 5.291 | 4.073 | 0.149 | – | – | – | – |
| 1810-31* E | 0.09 | 1 | 3.875 | 39.136 | 4.029 | 0.072 | – | – | – | – |
| 1810-32* E | 0.05 | 2 | 2.469 | 9.099 | 4.187 | 0.072 | – | – | – | – |
| 1810-33* E | 0.06 | 1 | 2.602 | 24.169 | 4.426 | 0.141 | – | – | – | – |
| 1810-34* E | 0.91 | 2010 | 3.131 | 0.068 | 4.561 | 0.032 | 105.2 | 7.0 | 5.798 | 0.128 |
| 1810-35 E | 1.01 | 3 | 4.291 | 15.514 | 4.085 | 0.025 | – | – | – | – |
| 1810-36 E | 0.04 | 99 | 6.297 | 8.890 | 4.060 | 0.242 | – | – | – | – |
| 1810-37 E | 0.14 | 528 | 5.753 | 3.932 | 4.385 | 0.234 | – | – | – | – |
| 1810-38 E | 0.02 | 55 | 5.687 | 28.490 | 4.211 | 0.437 | – | – | – | – |
| 1810-39 E | 0.01 | 17 | 4.203 | 31.048 | 4.474 | 0.314 | – | – | – | – |
| 1810-40 E | 2.09 | 1586 | 3.993 | 0.049 | 4.993 | 0.037 | 132.5 | 6.2 | 6.814 | 0.146 |
| Mean: | ||||||||||
| 1810 D | 9.07 | 5332 | 3.107 | 0.030 | 5.922 | 0.0145 | 72.3 | 1.9 | 7.040 | 0.060 |
| 1810 E | 1.10 | 1088 | 3.690 | 0.105 | 4.724 | 0.0788 | 128.8 | 14.4 | 6.595 | 0.316 |
| Sample1841 | U (ppm) | U/Th | 230Th/238U | 2σ | 234U/238U | 2σ | Age (ka) | 2s (ka) | (234U/238U)i | 2σ |
| 1841-1 E | 2.51 | 78 | 4.415 | 3.252 | 5.851 | 0.035 | – | – | – | – |
| 1841-2 E | 1.96 | 51 | 4.268 | 7.631 | 5.842 | 0.044 | – | – | – | – |
| 1841-3 E | 2.37 | 218 | 4.319 | 0.041 | 5.871 | 0.021 | 115.5 | 3.5 | 7.758 | 0.090 |
| 1841-4 E | 1.88 | 350 | 4.261 | 0.046 | 5.891 | 0.016 | 112.6 | 3.6 | 7.730 | 0.082 |
| 1841-5 E | 2.5 | 214 | 4.378 | 0.045 | 5.846 | 0.032 | 118.7 | 4.3 | 7.784 | 0.124 |
| 1841-6 E | 2.5 | 12 | 4.428 | 2.744 | 5.881 | 0.044 | – | – | – | – |
| 1841-7 E | 2.4 | 63 | 4.484 | 1.744 | 5.946 | 0.044 | – | – | – | – |
| 1841-8 E | 2.14 | 47 | 4.499 | 2.467 | 5.962 | 0.037 | – | – | – | – |
| Mean: | ||||||||||
| 1841 E | 2.25 | 261 | 4.319 | 0.044 | 5.869 | 0.023 | 115.6 | 3.8 | 7.757 | 0.099 |