Box and whisker plots of log transformed As/Fe molar ratios.
(a) Box and whisker plots grouped according to stages I–VI. One Way Analysis of Variance (ANOVA) confirms statistically significant differences (p < 0.05) between the stages (supplementary Table 2). (b) Expanded stage IV box and whiskers plots progressing from about ~2.1 to 1.4 Ga. ANOVA suggests significant differences between the groups (p < 0.05). (c) Mn concentration in sediments reported before, during and after the Paleoproterozoic Huronian glaciations39 (see supplementary Table 1). Red and black arrows indicate Huronian and post-Huronian glaciation sediments, respectively. Inset shows variations with extreme icehouse values omitted.