Fig. 2. Measurement results from coral samples.

${}^{236}$U/${}^{238}$U (black squares) and ${}^{233}$U/${}^{238}$U atom ratio (gray dots) in the Kume coral core as a function of time. The measurement uncertainties shown are ±1 $\sigma$ (s.e.m.). The data points are connected by solid lines (bold for ${}^{236}$U) to guide the eye. The maximum at 1955 is not statistically significant and thus, not linked to the neighboring points.