Table 1.
Uncorrected age‡ | Corrected age§ | 230Th/U burial age | |||||||||||
Sample ID | Tablet | U (ppb) | 232Th (ppb) | (230Th /232Th)* | Initial (234U /238U)† | ± (2σ, ab.) | ka | ± (2σ), ka | ka | ± (2σ), ka | Ka | ± (2σ), ka | Included in age model? |
YFT1-1A | Outer | 160.13 | 0.11 | 3,162.48 | 1.0853 | 0.0039 | 115.43 | 1.96 | 115.41 | 1.96 | 116.1 | 3.4 | Y |
Inner | 113.32 | 0.11 | 2,262.61 | 1.0892 | 0.0038 | 114.34 | 1.90 | 114.31 | 1.90 | ||||
YFT1-1C | Outer | 160.06 | 0.10 | 3,333.70 | 1.0755 | 0.0035 | 113.26 | 1.04 | 113.24 | 1.04 | 114.5 | 2.2 | Y |
Inner | 115.33 | 0.11 | 2,285.56 | 1.0754 | 0.0033 | 111.11 | 2.55 | 111.08 | 2.55 | ||||
YFT1-1D | Outer | 154.51 | 0.00 | 1,375.46 | 1.0982 | 0.0031 | 110.46 | 1.66 | 110.42 | 1.66 | N/A | N | |
Inner | 115.31 | 0.00 | 1,173.90 | 1.1230 | 0.0036 | 115.82 | 1.43 | 115.77 | 1.44 | ||||
YFT1-1E | Outer | 69.41 | 0.00 | 1,771.95 | 1.0884 | 0.0044 | 107.57 | 1.29 | 107.55 | 1.29 | N/A | N | |
Inner | 58.78 | 0.00 | 2,307.78 | 1.0827 | 0.0037 | 110.86 | 1.19 | 110.84 | 1.19 | ||||
YFT1-3C | Outer | 91.11 | 0.06 | 3,091.88 | 1.0849 | 0.0038 | 113.57 | 1.11 | 113.56 | 1.11 | 114.3 | 0.9 | Y |
Inner | 58.37 | 0.07 | 1,843.26 | 1.0899 | 0.0056 | 115.05 | 1.36 | 115.02 | 1.36 | ||||
YFT1-6D | Outer | 46.38 | 0.26 | 419.50 | 1.1860 | 0.0046 | 118.25 | 0.98 | 118.12 | 0.98 | 118.2 | 0.8 | Y |
Inner | 34.67 | 0.26 | 318.11 | 1.1961 | 0.0070 | 118.45 | 1.56 | 118.28 | 1.57 | ||||
YFT1-6E | Outer | 46.92 | 0.34 | 324.26 | 1.1753 | 0.0093 | 117.81 | 1.99 | 117.65 | 1.99 | 118.2 | 3.2 | Y |
Inner | 31.72 | 0.38 | 194.33 | 1.1945 | 0.0090 | 116.92 | 1.84 | 116.65 | 1.84 | ||||
YFT1-10A | Outer | 29.98 | 1.37 | 52.14 | 1.2342 | 0.0240 | 115.02 | 3.86 | 113.95 | 3.88 | 114.6 | 6.4 | Y |
Inner | 24.80 | 0.79 | 74.46 | 1.2411 | 0.0108 | 113.60 | 2.45 | 112.87 | 2.48 | ||||
YFT1-10E | Outer | 32.50 | 0.56 | 149.89 | 1.3697 | 0.0061 | 113.89 | 1.46 | 113.53 | 1.47 | 115.1 | 3.0 | Y |
Inner | 27.37 | 0.36 | 187.21 | 1.3190 | 0.0064 | 111.97 | 1.67 | 111.69 | 1.68 | ||||
YFT1-12F | Outer | 17.39 | 0.69 | 58.93 | 1.2252 | 0.0054 | 110.93 | 2.12 | 109.99 | 2.18 | 110.2 | 3.3 | N |
Inner | 12.59 | 0.76 | 38.46 | 1.2301 | 0.0068 | 111.10 | 1.73 | 109.65 | 1.91 | ||||
YFT1-12G | Outer | 23.32 | 0.78 | 67.73 | 1.1545 | 0.0051 | 116.33 | 1.75 | 115.48 | 1.81 | 116.9 | 3.1 | Y |
Inner | 20.23 | 0.63 | 71.82 | 1.1512 | 0.0057 | 113.93 | 1.74 | 113.14 | 1.80 | ||||
YFT1-12I | Outer | 22.52 | 0.60 | 83.82 | 1.1553 | 0.0032 | 114.08 | 1.75 | 113.40 | 1.79 | 114.5 | 2.8 | Y |
Inner | 15.66 | 0.51 | 68.31 | 1.1595 | 0.0061 | 112.10 | 1.94 | 111.28 | 2.00 | ||||
YFT1-12J | Outer | 23.38 | 0.97 | 57.49 | 1.2356 | 0.0038 | 115.75 | 1.82 | 114.76 | 1.91 | 116.7 | 3.2 | Y |
Inner | 21.90 | 0.37 | 138.97 | 1.2242 | 0.0085 | 111.68 | 2.36 | 111.29 | 2.37 |
YFT1 OES naming convention: YFT1-[layer group][individual]. Reference SI Appendix for details of analytical methods and Dataset S1B for comprehensive data table.
All isotope ratios are activity ratios.
Initial (234U/238U) is back calculated from the measured ratio and the corrected age.230Th/U burial ages in italics are calculated from the weighted mean of two subsamples.
Uncorrected ages are calculated from measured ratios. Decay constants used for all ages are those of ref. 46 for 238U and ref. 47 for 230Th and 234U.
Detritus-corrected ages were corrected for U and 232Th from detritus using (232Th/238U) = 1.21 ± 0.60, (230Th/238U) = 1.0 ± 0.1, and (234U/238U) = 1.0 ± 0.1.