va">mixtures</span></span>
<span><span class="va">x</span> <span class="op">&lt;-</span> <span class="fu"><a href="https://rdrr.io/r/base/c.html" class="external-link">c</a></span><span class="op">(</span></span>
<span>  <span class="va">source_means_c</span><span class="op">[</span>, <span class="st">"meand13CPl"</span><span class="op">]</span> <span class="op">-</span> <span class="va">source_sds_c</span><span class="op">[</span>, <span class="st">"SDd13C"</span><span class="op">]</span>,</span>
<span>  <