Table 2. U/Pb data measured by sensitive high-resolution ion microprobe at the Australian National University. Label U Th Th/U 204Pb/206Pb 207Pb/206Pb 238U/206Pb Ä206 Age (ppm) (ppm) (%) (Ma) DS25 31 18.03' 115 56.09' Standard error in 11 standards was 0.64%. 1.1 2681 277 0.10 0.00008 ± 0.00002 0.0496 ± 0.0003 46.57 ± 0.52 0.11 ± 0.04 136.8 ± 1.5 1.2 4397 292 0.07 0.00005 ± 0.00001 0.0490 ± 0.0003 45.10 ± 0.51 0.01 ± 0.03 141.4 ± 1.6 1.3 572 644 1.13 0.00029 ± 0.00005 0.0677 ± 0.0007 12.44 ± 0.25 1.31 ± 0.09 492.0 ± 9.4 ¥ 1.4 1730 170 0.10 0.00155 ± 0.00012 0.0716 ± 0.0014 46.54 ± 0.49 2.88 ± 0.17 133.1 ± 1.4 2.1 159 121 0.76 0.00044 ± 0.00008 0.0654 ± 0.0007 8.89 ± 0.10 0.38 ± 0.08 684.5 ± 7.4 ¥ 3.1 157 111 0.71 0.00022 ± 0.00009 0.0660 ± 0.0007 8.47 ± 0.10 0.34 ± 0.09 717.1 ± 7.8 ¥ 4.1 158 161 1.02 0.00001 ± 0.00006 0.0661 ± 0.0007 8.71 ± 0.14 0.42 ± 0.08 697.8 ± 10.7 ¥ 5.1 122 45 0.37 0.00009 ± 0.00012 0.0624 ± 0.0012 10.98 ± 0.15 0.44 ± 0.14 559.3 ± 7.2 ¥ 6.1 174 125 0.72 0.00023 ± 0.00011 0.0659 ± 0.0007 10.41 ± 0.12 0.78 ± 0.09 587.0 ± 6.3 ¥ 7.1 174 163 0.94 0.00052 ± 0.00010 0.0662 ± 0.0006 8.31 ± 0.11 0.32 ± 0.07 730.2 ± 8.8 ¥ 8.1 118 91 0.78 0.00035 ± 0.00011 0.0648 ± 0.0008 9.44 ± 0.15 0.44 ± 0.09 646.5 ± 9.6 ¥ 9.1 219 114 0.52 0.00023 ± 0.00007 0.0649 ± 0.0005 9.80 ± 0.14 0.53 ± 0.07 623.4 ± 8.8 ¥ 10.1 236 153 0.65 0.00011 ± 0.00005 0.0663 ± 0.0005 8.99 ± 0.19 0.52 ± 0.06 676.7 ± 13.4 ¥ DS58 31 14.34' 116 20.39' Standard error in 13 standards was 0.33%. 1.1 521 238 0.46 0.00033 ± 0.00010 0.0497 ± 0.0005 50.84 ± 0.53 0.14 ± 0.06 125.4 ± 1.3 1.2 228 180 0.79 0.00050 ± 0.00026 0.0522 ± 0.0008 50.36 ± 0.69 0.46 ± 0.10 126.2 ± 1.7 2.1 104 88 0.85 0.00293 ± 0.00043 0.0687 ± 0.0028 49.82 ± 0.75 2.55 ± 0.36 124.9 ± 1.9 3.1 697 107 0.15 0.00003 ± 0.00001 0.0718 ± 0.0002 6.89 ± 0.09 0.44 ± 0.02 870.2 ± 10.4 ¥ 3.2 211 134 0.64 0.00095 ± 0.00021 0.0527 ± 0.0008 49.28 ± 0.62 0.52 ± 0.09 128.8 ± 1.6 4.1 176 132 0.75 0.00126 ± 0.00028 0.0531 ± 0.0008 48.26 ± 0.54 0.56 ± 0.10 131.5 ± 1.5 5.1 83 82 0.99 0.00270 ± 0.00038 0.0693 ± 0.0052 50.35 ± 2.40 2.64 ± 0.65 123.5 ± 5.9 6.1 195 122 0.63 0.00119 ± 0.00025 0.0754 ± 0.0058 47.61 ± 0.81 3.37 ± 0.73 129.5 ± 2.4 7.1 417 221 0.53 0.00011 ± 0.00009 0.0482 ± 0.0010 49.30 ± 0.52 -0.05 ± -0.13 129.5 ± 1.4 8.1 251 260 1.04 0.00047 ± 0.00015 0.0495 ± 0.0006 49.70 ± 0.54 0.12 ± 0.08 128.3 ± 1.4 9.1 105 114 1.09 0.00141 ± 0.00042 0.0714 ± 0.0039 47.21 ± 0.75 2.87 ± 0.49 131.3 ± 2.2 10.1 152 134 0.89 0.00127 ± 0.00036 0.0551 ± 0.0009 48.19 ± 0.55 0.82 ± 0.12 131.3 ± 1.5 DS72 30 55.18' 116 22.11' Standard error in 13 standards was 0.33%. 1.1 278 173 0.62 0.00007 ± 0.00013 0.0513 ± 0.0010 46.43 ± 1.04 0.31 ± 0.13 136.9 ± 3.0 1.2 245 167 0.68 0.00013 ± 0.00003 0.0666 ± 0.0003 7.69 ± 0.08 0.14 ± 0.04 787.0 ± 7.6 ¥ 1.3 127 92 0.73 0.00024 ± 0.00007 0.0663 ± 0.0008 8.20 ± 0.32 0.29 ± 0.09 739.9 ± 27.5 ¥ 1.4 166 100 0.60 0.00215 ± 0.00048 0.0613 ± 0.0049 44.25 ± 2.96 1.58 ± 0.62 141.8 ± 9.4 2.1 163 202 1.24 0.00063 ± 0.00025 0.0581 ± 0.0009 47.41 ± 0.53 1.18 ± 0.11 133.0 ± 1.5 3.1 211 407 1.92 0.00052 ± 0.00019 0.0590 ± 0.0008 49.13 ± 0.62 1.31 ± 0.10 128.2 ± 1.6 4.1 126 139 1.10 0.00071 ± 0.00024 0.0549 ± 0.0009 49.34 ± 0.57 0.80 ± 0.12 128.3 ± 1.5 5.1 126 191 1.51 0.00117 ± 0.00030 0.0616 ± 0.0018 47.45 ± 0.65 1.64 ± 0.23 132.3 ± 1.8 6.1 453 98 0.22 0.00007 ± 0.00003 0.0631 ± 0.0003 14.79 ± 0.27 0.98 ± 0.04 417.7 ± 7.5 ¥ 6.2 181 99 0.55 0.00018 ± 0.00004 0.0683 ± 0.0007 7.72 ± 0.09 0.37 ± 0.08 782.3 ± 8.5 ¥ 7.1 181 252 1.39 0.00046 ± 0.00018 0.0519 ± 0.0008 48.57 ± 0.54 0.41 ± 0.10 130.9 ± 1.5 8.1 138 161 1.17 -0.00025 ± 0.00028 0.0534 ± 0.0009 48.57 ± 0.56 0.60 ± 0.12 130.6 ± 1.5 8.2 145 184 1.27 0.00140 ± 0.00034 0.0546 ± 0.0009 46.94 ± 0.54 0.74 ± 0.12 134.9 ± 1.5 9.1 135 112 0.83 0.00185 ± 0.00036 0.0646 ± 0.0022 46.68 ± 0.54 2.01 ± 0.28 133.9 ± 1.6 10.1 287 646 2.25 0.00043 ± 0.00023 0.0511 ± 0.0015 48.19 ± 0.58 0.31 ± 0.19 132.0 ± 1.6 11.1 153 150 0.98 0.00045 ± 0.00036 0.0537 ± 0.0008 47.76 ± 0.64 0.63 ± 0.10 132.7 ± 1.8 12.1 64 101 1.58 0.00064 ± 0.00055 0.0623 ± 0.0015 47.21 ± 0.61 1.71 ± 0.19 132.8 ± 1.7 DS81 30 49.23' 116 04.42' Standard error in 11 standards was 0.64%. 1.1 34 44 1.29 0.00219 ± 0.00122 0.0704 ± 0.0035 48.21 ± 1.07 2.75 ± 0.44 128.7 ± 2.9 2.1 127 250 1.97 0.00050 ± 0.00042 0.0551 ± 0.0015 46.94 ± 0.68 0.80 ± 0.19 134.8 ± 1.9 3.1 46 55 1.19 0.00203 ± 0.00108 0.0699 ± 0.0046 46.74 ± 1.49 2.66 ± 0.58 132.9 ± 4.3 4.1 103 140 1.36 0.00134 ± 0.00059 0.0530 ± 0.0028 47.27 ± 0.72 0.54 ± 0.35 134.2 ± 2.1 5.1 41 41 0.99 0.00224 ± 0.00096 0.0755 ± 0.0030 46.70 ± 0.92 3.38 ± 0.38 132.0 ± 2.6 6.1 49 68 1.37 0.00473 ± 0.00158 0.0604 ± 0.0025 46.34 ± 0.87 1.47 ± 0.31 135.6 ± 2.5 7.1 119 181 1.52 0.00119 ± 0.00034 0.0533 ± 0.0014 46.21 ± 0.66 0.57 ± 0.18 137.2 ± 2.0 8.1 105 163 1.55 0.00134 ± 0.00044 0.0539 ± 0.0015 43.38 ± 0.64 0.62 ± 0.19 146.0 ± 2.1 ¥ 9.1 47 52 1.12 0.00283 ± 0.00147 0.0479 ± 0.0023 46.92 ± 0.87 -0.12 ± 0.29 136.1 ± 2.5 10.1 88 119 1.34 0.00424 ± 0.00088 0.0969 ± 0.0059 45.86 ± 1.43 6.08 ± 0.74 130.7 ± 4.2 DS107 30 32.48' 116 17.01' 1.1 1352 22 0.02 0.00044 ± 0.00020 0.0605 ± 0.0008 25.73 ± 0.40 1.18 ± 0.10 242.9 ± 3.7 1.2 53 56 1.07 0.00001 ± 0.00069 0.0816 ± 0.0021 7.86 ± 0.17 2.01 ± 0.26 757.3 ± 15.6 ¥ 2.1 1645 22 0.01 0.00001 ± 0.00013 0.0523 ± 0.0005 29.05 ± 0.36 0.22 ± 0.07 217.7 ± 2.7 3.1 1135 17 0.02 0.00051 ± 0.00024 0.0617 ± 0.0012 26.31 ± 0.31 1.33 ± 0.16 237.3 ± 2.7 4.1 283 98 0.35 0.00001 ± 0.00016 0.0703 ± 0.0016 9.28 ± 0.13 1.07 ± 0.20 653.2 ± 8.5 ¥ 4.2 1018 19 0.02 0.00202 ± 0.00067 0.0935 ± 0.0017 25.58 ± 0.30 5.30 ± 0.21 234.3 ± 2.8 5.1 1086 12 0.01 0.00027 ± 0.00028 0.0536 ± 0.0011 27.99 ± 0.34 0.36 ± 0.14 225.5 ± 2.7 6.1 1283 28 0.02 0.00001 ± 0.00015 0.0511 ± 0.0011 27.32 ± 0.32 0.04 ± 0.14 231.6 ± 2.7 6.2 153 81 0.53 0.00001 ± 0.00037 0.0737 ± 0.0014 11.42 ± 0.20 1.89 ± 0.18 531.3 ± 8.8 ¥ 6.3 1090 11 0.01 0.00001 ± 0.00021 0.0579 ± 0.0007 27.43 ± 0.31 0.89 ± 0.08 228.8 ± 2.6 7.1 50 33 0.67 0.00001 ± 0.00138 0.0777 ± 0.0038 9.58 ± 0.22 2.03 ± 0.46 627.6 ± 14.1 ¥ 8.1 1093 14 0.01 0.00070 ± 0.00039 0.0666 ± 0.0009 26.72 ± 0.30 1.96 ± 0.11 232.3 ± 2.6 9.1 104 153 1.47 0.00062 ± 0.00078 0.0742 ± 0.0019 7.00 ± 0.15 0.78 ± 0.23 854.7 ± 17.0 ¥ 10.1 1051 19 0.02 0.00015 ± 0.00017 0.0549 ± 0.0012 27.02 ± 0.33 0.51 ± 0.15 233.1 ± 2.9 11.1 1706 41 0.02 0.00022 ± 0.00019 0.0588 ± 0.0009 25.89 ± 0.31 0.97 ± 0.11 242.0 ± 2.9 12.1 1109 12 0.01 0.00026 ± 0.00021 0.0537 ± 0.0013 26.72 ± 0.33 0.35 ± 0.16 236.0 ± 2.9 13.1 1240 28 0.02 0.00159 ± 0.00049 0.0720 ± 0.0008 29.59 ± 0.35 2.70 ± 0.10 208.5 ± 2.4 14.1 1259 15 0.01 0.00001 ± 0.00031 0.0529 ± 0.0010 26.33 ± 0.34 0.24 ± 0.12 239.8 ± 3.0 15.1 1070 17 0.02 0.00001 ± 0.00013 0.0538 ± 0.0012 26.32 ± 0.36 0.35 ± 0.16 239.5 ± 3.2 16.1 1243 14 0.01 0.00129 ± 0.00044 0.0769 ± 0.0010 28.13 ± 0.35 3.29 ± 0.13 217.9 ± 2.7 17.1 460 197 0.43 0.00018 ± 0.00040 0.0582 ± 0.0012 16.35 ± 0.21 0.48 ± 0.14 380.9 ± 4.8 ¥ 18.1 196 254 1.29 0.00001 ± 0.00031 0.0686 ± 0.0010 8.36 ± 0.14 0.60 ± 0.12 724.3 ± 11.1 ¥ 19.1 165 105 0.63 0.00036 ± 0.00027 0.0731 ± 0.0011 7.58 ± 0.12 0.89 ± 0.14 792.4 ± 12.0 ¥ 20.1 165 199 1.20 0.00000 ± 0.00021 0.0696 ± 0.0021 8.92 ± 0.16 0.89 ± 0.26 678.8 ± 11.5 ¥ 21.1 258 332 1.29 0.00020 ± 0.00017 0.0679 ± 0.0009 7.72 ± 0.11 0.31 ± 0.10 782.9 ± 11.0 ¥ DS150 30 53.98' 115 45.15' Standard error in 13 standards was 0.33%. 1.1 250 82 0.33 0.00058 ± 0.00015 0.0527 ± 0.0007 47.30 ± 0.51 0.50 ± 0.08 134.2 ± 1.5 1.2 453 162 0.36 0.00038 ± 0.00011 0.0508 ± 0.0005 47.70 ± 0.50 0.26 ± 0.06 133.4 ± 1.4 1.3 519 245 0.47 0.00039 ± 0.00008 0.0515 ± 0.0005 47.31 ± 0.52 0.35 ± 0.06 134.4 ± 1.5 2.1 220 70 0.32 0.00092 ± 0.00025 0.0533 ± 0.0007 47.96 ± 0.53 0.59 ± 0.09 132.3 ± 1.5 2.2 132 20 0.15 0.00058 ± 0.00040 0.0607 ± 0.0026 48.79 ± 1.92 1.52 ± 0.33 128.8 ± 5.0 3.1 265 163 0.61 0.00054 ± 0.00021 0.0541 ± 0.0007 47.91 ± 0.52 0.69 ± 0.08 132.3 ± 1.4 3.2 122 63 0.52 0.00142 ± 0.00037 0.0569 ± 0.0010 47.97 ± 0.56 1.04 ± 0.13 131.6 ± 1.5 DS158 30 45.25' 115 44.57' Standard error in 13 standards was 0.33%. 1.1 66 2.0 0.03 0.00124 ± 0.00038 0.0589 ± 0.0027 26.63 ± 0.50 1.01 ± 0.33 235.3 ± 4.4 2.1 274 4.7 0.02 0.00004 ± 0.00011 0.0520 ± 0.0005 27.53 ± 0.37 0.16 ± 0.07 229.7 ± 3.0 3.1 110 2.9 0.03 0.00053 ± 0.00040 0.0558 ± 0.0008 28.21 ± 0.39 0.66 ± 0.10 223.1 ± 3.0 4.1 81 2.3 0.03 0.00078 ± 0.00044 0.0578 ± 0.0010 28.79 ± 0.34 0.91 ± 0.12 218.1 ± 2.5 5.1 65 2.3 0.04 0.00213 ± 0.00056 0.0687 ± 0.0037 22.34 ± 1.52 2.12 ± 0.46 276.4 ± 18.5 6.1 93 2.3 0.03 0.00085 ± 0.00025 0.0589 ± 0.0017 25.21 ± 0.71 0.97 ± 0.22 248.3 ± 6.8 6.2 143 182.3 1.27 0.00033 ± 0.00008 0.0647 ± 0.0005 12.17 ± 0.14 0.90 ± 0.06 504.7 ± 5.4 ¥ 7.1 63 1.7 0.03 0.00254 ± 0.00033 0.0871 ± 0.0057 29.00 ± 0.41 4.61 ± 0.71 208.7 ± 3.3 7.2 104 9.3 0.09 0.00102 ± 0.00023 0.0678 ± 0.0016 27.22 ± 0.31 2.14 ± 0.20 227.7 ± 2.6 8.1 73 2.3 0.03 0.00129 ± 0.00023 0.0596 ± 0.0010 28.55 ± 0.33 1.15 ± 0.12 219.4 ± 2.5 8.2 159 6.2 0.04 0.00124 ± 0.00029 0.0586 ± 0.0021 26.87 ± 0.35 0.98 ± 0.26 233.3 ± 3.1 DS163 30 46.75' 115 25.45' Standard error in 11 standards was 0.64%. 1.1 358 485 1.36 0.00011 ± 0.00003 0.0667 ± 0.0005 8.01 ± 0.17 0.26 ± 0.06 756.3 ± 15.2 ¥ 2.1 76 92 1.21 0.00001 ± 0.00017 0.0678 ± 0.0012 7.88 ± 0.18 0.37 ± 0.14 767.2 ± 16.3 ¥ 3.1 444 232 0.52 0.00011 ± 0.00003 0.0673 ± 0.0005 8.11 ± 0.17 0.38 ± 0.06 747.2 ± 14.4 ¥ 4.1 233 84 0.36 0.00029 ± 0.00012 0.0687 ± 0.0029 19.63 ± 0.47 1.93 ± 0.36 314.3 ± 7.4 ¥ 5.1 83 108 1.30 0.00004 ± 0.00010 0.0663 ± 0.0007 8.14 ± 0.19 0.26 ± 0.09 745.2 ± 16.1 ¥ 6.1 330 154 0.47 -0.00002 ± 0.00002 0.0664 ± 0.0003 7.50 ± 0.17 0.05 ± 0.04 806.5 ± 17.0 ¥ 6.1A 683 120 0.18 0.00013 ± 0.00002 0.0664 ± 0.0003 8.64 ± 0.15 0.44 ± 0.04 703.3 ± 11.3 ¥ 6.2A 1328 51 0.04 0.00010 ± 0.00004 0.0501 ± 0.0004 48.51 ± 0.60 0.17 ± 0.05 131.3 ± 1.6 6.3A 1183 45 0.04 0.00021 ± 0.00005 0.0502 ± 0.0005 50.11 ± 0.59 0.20 ± 0.06 127.1 ± 1.5 7.1 1858 675 0.36 0.00002 ± 0.00002 0.0732 ± 0.0030 16.22 ± 0.67 2.33 ± 0.38 377.0 ± 15.1 ¥ 8.1 755 25 0.03 0.00002 ± 0.00004 0.0518 ± 0.0005 49.09 ± 1.00 0.39 ± 0.07 129.5 ± 2.6 8.1A 1394 107 0.08 0.00019 ± 0.00007 0.0562 ± 0.0004 32.67 ± 0.37 0.78 ± 0.05 192.9 ± 2.2 ¥ 9.1 493 195 0.40 -0.00000 ± 0.00002 0.0658 ± 0.0003 8.97 ± 0.20 0.44 ± 0.04 678.3 ± 14.1 ¥ 9.2 2284 1319 0.58 0.00015 ± 0.00002 0.0654 ± 0.0002 13.38 ± 0.22 1.13 ± 0.03 459.5 ± 7.3 ¥ 10.1 640 352 0.55 0.00009 ± 0.00002 0.0651 ± 0.0003 10.12 ± 0.16 0.62 ± 0.04 604.1 ± 8.9 ¥ 11.1 67 54 0.80 0.00042 ± 0.00015 0.0692 ± 0.0009 7.98 ± 0.12 0.59 ± 0.11 757.2 ± 10.6 ¥ 12.1 2184 605 0.28 0.00001 ± 0.00001 0.0642 ± 0.0002 9.71 ± 0.12 0.43 ± 0.02 629.1 ± 7.4 ¥ Number before decimal identifies a specific grain; number after decimal identifies specific analysis within that grain. 204Pb/206Pb, 207Pb/206Pb, 238U/206Pb ratios are as measured (i.e., no common Pb correction) Ä206 is the percentage of common Pb as estimated from the difference between the measured 207Pb/206Pb ratio and the extrapolated concordant age (207Pb method). Age: 206/238 age corrected for common Pb as given by Ä206. ¥ inheritance components All errors ± 1s.