Fig. 1
From: Early Palaeozoic ocean anoxia and global warming driven by the evolution of shallow burrowing
Compilation of geochemical data from the Neoproterozoic into the Palaeozic. a Mo abundances, as compiled by ref. 29. Higher oxygen levels lead to higher abundances of Mo. Note that other proxies providing support for the ocean oxygenation state outlined here are compiled in Supplementary Fig. 1. b Sulphate-S isotopes (δ34SSO4) as compiled by ref. 69. δ34SSO4 increases through the Cambrian, with a return to lighter values at the GOBE. c Pyrite fraction of sulphur burial (fpyr = pyrite burial/(pyrite burial + gypsum burial)), full range of estimates, as presented in ref. 44. d Carbonate-C isotopes (δ13Ccarb) as compiled by ref. 70. Higher values indicate a higher rate of organic carbon burial. e Mixed layer depth, reproduced from ref. 7. Black lines on panels b and d are local regression (LOESS) fits. Grey shaded areas indicate the Cambrian explosion (540–521 Ma) and the Great Ordovician Biodiversification Event (GOBE; 470–450 Ma). Blue shaded line indicates the Hirnantian glaciation
