Neoproterozoic to early Phanerozoic rise in island arc redox state due to deep ocean oxygenation and increased marine sulfate levels.

ABSTRACT: A rise in atmospheric O₂ levels between 800 and 400 Ma is thought to have oxygenated the deep oceans, ushered in modern biogeochemical cycles, and led to the diversification of animals. Over the same time interval, marine sulfate concentrations are also thought to have increased to near-modern levels. We present compiled data that indicate Phanerozoic island arc igneous rocks are more oxidized (Fe³⁺/ΣFe ratios are elevated by 0.12) vs. Precambrian equivalents. We propose this elevation is due to increases in deep-ocean O₂ and marine sulfate concentrations between 800 and 400 Ma, which oxidized oceanic crust on the seafloor. Once subducted, this material oxidized the subarc mantle, increasing the redox state of island arc parental melts, and thus igneous isl

SUBMITTER: Stolper DA 

PROVIDER: S-EPMC6500123 | biostudies-literature | 2019 Apr

REPOSITORIES: biostudies-literature