Abstract

Figure 1: Environmental and biotic variables related to Phanerozoic dolomite abundance. (A) Variations in dolomite abundance (results of 10,000 resampling runs) throughout the Phanerozoic. Blue dots indicate mean values, and error bars indicate 95% confidence interval. (B) Sulfur-isotope composition of Phanerozoic marine carbonate rocks. (C) Diversity of marine benthic invertebrates and oceanic redox conditions in Phanerozoic history. Yellow bars highlight five mass extinctions. Sulfur isotope data are from Kampschulte and Strauss (2004),Prokoph et al. (2008), and Hannisdal and Peters (2011); note that almost all sulfur isotope data (171 out of 186) are sourced from the same regions where carbonate sections presented in our geodata set are located (see Dataset S1 in the Supplemental Material [see ^{footnote 1}]; see also Kampschulte and Strauss, 2004). Paleontology data are from Paleobiology Database (PBDB; https://paleobiodb.org). Ocean anoxic events are from Whiteside and Grice (2016) and Song et al.(2017), with modifications. Cam—Cambrian; Or—Ordovician; S—Silurian; D—Devonian; Car—Carboniferous; P—Permian; Tr—Triassic; Jur—Jurassic; Cre—Cretaceous; Pg—Paleogene; N—Neogene.

Figure 2: (A) Dolomite abundance versus genus richness of marine benthic invertebrates, showing negative correlation (p = 0.007). (B) Dolomite abundance versus rate of change of δ³⁴S, showing positive correlation (p = 0.002) (pink dots spanning the middle Cambrian to Early Ordovician were excluded from analysis; see the Discussion in the text), where an increase in δ³⁴S is a good proxy of enhanced pyrite burial caused by intense sulfate reductions.