Figure 6
Integrated compilation of diverse geochemical indices with the biodiversity data. (A) Geochemical indices through geologic time. Mo concentrations were picked from refs 4 and 14, and time-averaged U concentrations were selected from the data of ref. 5, including data of this investigation. The composite curve of secular trends of δ15N are according to ref. 24. The curve of atmospheric oxygen levels relative to present is according to refs 2, 3 and 7. (B) Concentrations of Mo and U and MoEF/UEF through time (541–515 Ma); compilation of δ15N values from a range of depositional environments in the Early Cambrian Yangtze Sea (541–515 Ma). N isotopes are compiled from refs 20, 21 and this study. (C) Comparative bioturbation index and ichnodiversity data (referred to ref. 13); animal diversity from ref. 42 and SSF diversity data from ref. 43. The ages of glacial and green-house intervals are according to ref. 24. The white arrows in (B) represent the overall variation tendency of δ15N values.
