Fig. 1

Lithostratigraphic profile of the Lijiatuo section and C- and Si stable isotope ratios of chert and siliceous shales and the paleogeographic setting of the site. The Lijiatuo section a is located in the continental slope-to-basin setting at the Yangtze Platform b and contains chert, siliceous shales and regional, Lower Cambrian marker horizons, i.e., phosphate bearing units (Phos) and a Ni-Mo layer as well as an ash layer (Ash) dated to 546 ± 12 Ma²⁶. The sedimentary facies of the section changes towards higher TOC concentrations as shown by symbol colour (blue: <5 wt%, red: 15 wt%) as well as towards higher the clay-mineral contents (represented by the Al₂O₃ concentration, increasing symbol size). Scale bar, 10 m