Fig. 3

Geochemical data from the Shennongjia Group. Samples are plotted sequentially and relative to stratigraphic position (from top to bottom), but not as function of exact stratigraphic position, but rather by sample number (1, 2, 3, etc.). Therefore, the depth trends in the figure and do not reflect actual placement in the stratigraphy (see Fig. 1). The gray vertical bar in the δ⁵³Cr plot represents the crustal average value³⁹