Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain
the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in
Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles
and JavaScript.
The alternative text for this image may have been generated using AI.
a, b using metal element indicator34; c, d using rare earth elements and Y indicator33. The Ce anomaly (Ce/Ce*) is calculated using the equation Ce/Ce* = Cen/(Prn2/Ndn), where n denotes normalization of each concentration against the post-Archean Australian shale (PAAS)51.