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Table 1 Uranium and thorium isotopic compositions and 230Th ages (before 1950 AD) for subsamples of stalagmite FG02 by MC-ICP-MS

From: Stalagmite evidence for East Asian winter monsoon variability and 18O-depleted surface water in the Japan Sea during the last glacial period

Horizon (mm) Weight (g) 238U (ppb) 232Th (ppt) δ234U (measured)a [230Th/238U] (activity)c [230Th/232Th] (ppm)d Age (uncorrected) Age (corrected)c,e δ234Uinitial (corrected)b
9.5 0.2257 6.01 ± 0.00 3818 ± 13.4 387.7 ± 2.4 0.2987 ± 0.0129 7.8 ± 0.3 26165 ± 1265 13537 ± 6838 402.8 ± 8.0
29.0 0.2416 9.33 ± 0.01 1247 ± 4.2 423.9 ± 2.2 0.2957 ± 0.0056 36.5 ± 0.7 25126 ± 530 22665 ± 1349 452.0 ± 2.9
61.0 0.2635 8.21 ± 0.01 543 ± 2.9 407.2 ± 3.1 0.2889 ± 0.0039 72.1 ± 1.0 24810 ± 377 23585 ± 720 435.2 ± 3.4
80.7 0.2880 7.78 ± 0.02 446 ± 2.6 436.7 ± 3.9 0.2778 ± 0.0030 80.0 ± 1.0 23213 ± 283 22173 ± 593 465.0 ± 4.2
93.2 0.2944 6.32 ± 0.03 293 ± 2.4 443.8 ± 7.1 0.2948 ± 0.0027 105.1 ± 1.2 24642 ± 282 23809 ± 501 474.7 ± 7.6
120.7 0.3347 6.08 ± 0.03 754 ± 4.2 430.8 ± 8.1 0.2993 ± 0.0053 39.8 ± 0.7 25323 ± 524 23053 ± 1255 459.8 ± 8.8
148.5 0.2848 6.07 ± 0.03 431 ± 2.8 483.1 ± 8.9 0.3159 ± 0.0048 73.4 ± 1.2 25812 ± 472 24567 ± 779 517.8 ± 9.6
159.5 0.2749 6.32 ± 0.04 233 ± 2.6 494.0 ± 11.4 0.3349 ± 0.0032 149.9 ± 2.0 27329 ± 381 26691 ± 492 532.8 ± 12.4
178.7 0.2364 5.80 ± 0.04 669 ± 4.1 484.4 ± 10.9 0.3733 ± 0.0064 53.5 ± 0.9 31127 ± 660 29111 ± 1202 525.9 ± 12.0
  1. a234U = ([234 U/238 U] activity−1) × 1000.
  2. b234Uinitial corrected was calculated based on 230Th age (T), i.e., 234Uinitial = 234Umeasured × e 234*T, and T is corrected age
  3. c[230Th/238 U]activity = 1 − e−230 T + (234Umeasured/1000)[230/(230–234)](1 − e − (230–234) T), where T is the age. Decay constants are 9.1577 × 10−6 year-1 for 230Th, 2.8263 × 10–6 year-1 for 234 U (Cheng et al. 2013), and 1.55125 × 10–10 year-1 for 238 U (Jaffey et al. 1971)
  4. dThe degree of detrital 230Th contamination is indicated by the [230Th/232Th] atomic ratio instead of the activity ratio
  5. eAge corrections were calculated using an estimated atomic 230Th/232Th ratio of 4 ± 2 ppm