Fig. S1.

Geological map of the Transvaal Supergroup preserved on the Kaapvaal Craton with a geographical insert, modified from refs. 53 and 68. The position of cores where Δ³⁶S/Δ³³S–δ¹³C covariation has been previously reported (core GKF01, ref. 9; core BH1-Sacha, ref. 8) is indicated by labeled stars. Additionally the extra Agouron core (GKP01) that we discuss below in terms of chronological constraints is also given. The shallow-water Ghaap plateau facies are separated from their deep-water equivalents by the fault at Griquatown (GFZ; refs. 37 and 53), hence the different stratigraphic nomenclature between Zerkle et al. (9) and Izon et al. (8).