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<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>Christopher C. Fuller</dc:contributor>
  <dc:contributor>Stacey A. Archfield</dc:contributor>
  <dc:creator>Judith Z. Drexler</dc:creator>
  <dc:date>2018</dc:date>
  <dc:description>&lt;p&gt;&lt;span&gt;The peak fallout in 1963 of the&amp;nbsp;radionuclide&amp;nbsp;&lt;/span&gt;&lt;sup&gt;137&lt;/sup&gt;&lt;span&gt;Cs has been used to date lake, reservoir,&amp;nbsp;continental shelf, and&amp;nbsp;wetland&amp;nbsp;sedimentary deposits. In wetlands such dating is used to project the ability of wetlands to keep pace with&amp;nbsp;sea level rise&amp;nbsp;and develop strategies for mitigating carbon pollution using biological&amp;nbsp;carbon sequestration. Here we demonstrate that reliable&amp;nbsp;&lt;/span&gt;&lt;sup&gt;137&lt;/sup&gt;&lt;span&gt;Cs profiles are increasingly difficult to obtain from&amp;nbsp;wetland soils. Among 58 soil cores recently collected from a range of wetland types and&amp;nbsp;&lt;/span&gt;&lt;sup&gt;137&lt;/sup&gt;&lt;span&gt;Cs fallout densities across the United States, 25% contain no identifiable&amp;nbsp;&lt;/span&gt;&lt;sup&gt;137&lt;/sup&gt;&lt;span&gt;Cs peaks. Less than 40% of&amp;nbsp;&lt;/span&gt;&lt;sup&gt;137&lt;/sup&gt;&lt;span&gt;Cs ages are consistent with&amp;nbsp;&lt;/span&gt;&lt;sup&gt;210&lt;/sup&gt;&lt;span&gt;Pb dating. We provide a new measure of&amp;nbsp;&lt;/span&gt;&lt;sup&gt;137&lt;/sup&gt;&lt;span&gt;Cs peak clarity (τ) for our core dataset by comparing the 50% interquartile range of data around the&amp;nbsp;&lt;/span&gt;&lt;sup&gt;137&lt;/sup&gt;&lt;span&gt;Cs peak for “ideal” cores profiles determined using&amp;nbsp;&lt;/span&gt;&lt;sup&gt;137&lt;/sup&gt;&lt;span&gt;Cs fallout data to that of observed core profiles. Our results show that overall τ is approximately 10 times greater for observed cores than ideal cores. The deterioration in the&amp;nbsp;&lt;/span&gt;&lt;sup&gt;137&lt;/sup&gt;&lt;span&gt;Cs peak has occurred due to radionuclide decay,&amp;nbsp;&lt;/span&gt;&lt;sup&gt;137&lt;/sup&gt;&lt;span&gt;Cs migration&amp;nbsp;&lt;/span&gt;&lt;i&gt;in situ&lt;/i&gt;&lt;span&gt;, which is ubiquitous in this study, and&amp;nbsp;&lt;/span&gt;&lt;sup&gt;137&lt;/sup&gt;&lt;span&gt;Cs amendments from surface waters. Such deterioration likely extends to both Mexican and non-permafrost, Canadian wetlands. We recommend continued use of&amp;nbsp;&lt;/span&gt;&lt;sup&gt;137&lt;/sup&gt;&lt;span&gt;Cs&amp;nbsp;&lt;/span&gt;&lt;i&gt;only&lt;/i&gt;&lt;span&gt;&amp;nbsp;if the full bound of dating uncertainty for both&amp;nbsp;&lt;/span&gt;&lt;sup&gt;137&lt;/sup&gt;&lt;span&gt;Cs and an additional method such as&amp;nbsp;&lt;/span&gt;&lt;sup&gt;210&lt;/sup&gt;&lt;span&gt;Pb is propagated into estimates of wetland vertical&amp;nbsp;accretion&amp;nbsp;and carbon sequestration.&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1016/j.quascirev.2018.08.028</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>Elsevier</dc:publisher>
  <dc:title>The approaching obsolescence of 137Cs dating of wetland soils in North America</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>