Table 1 Atom probe data from Pb clusters.

Tip refers to the specimen number (see Figs. 1 and 3). Roman numerals correspond to clusters shown in Fig. 3. Pb counts are the number of background-corrected 206Pb and 207Pb atoms counted per cluster. Background-corrected 207Pb/206Pb ratios are reported with 1σ uncertainty. 207Pb/206Pb dates for each cluster are reported with 1σ uncertainty. The sum of the clusters is labeled “Total.”

TipClusterPb counts
(atoms)
Corrected 207Pb/206Pb
ratio ±1σ
Date (Ma)
±1σ
206Pb207Pb
M5I564840.149 ± 0.0192334 ± 210
II176240.134 ± 0.0332151 ± 443
M4VIII93150.160 ± 0.0532456 ± 590
VI9001420.157 ± 0.0152424 ± 163
III7861070.136 ± 0.0162177 ± 221
M2IV8241080.131 ± 0.0152111 ± 202
VII126170.134 ± 0.0382151 ± 515
M1V87110.123 ± 0.0462000 ± 713
Total35565070.142 ± 0.00742258 ± 90