The version of the supplementary materials made available for download at the time of this article’s original publication omitted some key information pertaining to the two sets of “Δ¹⁴ (‰)” and “Error” columns given for each sample.

Δ¹⁴C data for this study were measured during two time periods, first in March 2017 and then in October 2017. Four specimens were measured twice, once during each period, while all others were measured in October 2017 only. The original spreadsheet provided only the October 2017 Δ¹⁴C data measurements (in columns C and D) and the summed data (in columns E and F).

Corrected supplementary materials have been made available for download. For the four specimens that were sampled twice, sample information for the March 2017 Δ¹⁴C measurement has been added in columns E–H. The October 2017 and summed data remain unchanged.

Additionally, the supplementary table has been given a title for context. This table is now labeled as follows:

Supplementary Table 1 Summed Δ¹⁴C data (columns I and J) for Arizona, USA in Figures 2 and 3.

The authors apologize for this error.