Constraining the rise of oxygen with oxygen isotopes.

ABSTRACT: After permanent atmospheric oxygenation, anomalous sulfur isotope compositions were lost from sedimentary rocks, demonstrating that atmospheric chemistry ceded its control of Earth's surficial sulfur cycle to weathering. However, mixed signals of anoxia and oxygenation in the sulfur isotope record between 2.5 to 2.3 billion years (Ga) ago require independent clarification, for example via oxygen isotopes in sulfate. Here we show <2.31 Ga sedimentary barium sulfates (barites) from the Turee Creek Basin, W. Australia with positive sulfur isotope anomalies of ∆³³S up to + 1.55‰ and low δ¹⁸O down to -19.5‰. The unequivocal origin of this combination of signals is sulfide oxidation in meteoric water. Geochemical and sedimentary evidence suggests that these S-isotope anomal

SUBMITTER: Killingsworth BA 

PROVIDER: S-EPMC6820740 | biostudies-literature | 2019 Oct

REPOSITORIES: biostudies-literature