Depth-dependent δ 13C trends in platform and slope settings of the Campbellrand-Malmani carbonate platform and possible implications for Early Earth oxygenation

摘要

Highlights?Carbon cycle of Neoarchean carbonate platform and potential oxygen oasis.?Carbon isotopes reveal a shift to aerobic biosphere and increasing oxidation state.?Rare earth element patterns reveal decrease in open ocean water influx.?Rimmed margin architecture was crucial for evolution of aerobic ecosystems.AbstractThe evolution of oxygenic photosynthesis is widely seen as the major biological factor for the profound shift from reducing to slightly oxidizing conditions in Earth’s atmosphere during the Archean-Proterozoic transition period. The delay from the first biogenic production of oxygen and the permanent oxidation of Earth’s atmosphere during the early Paleoproteorozoic Great Oxidation Event (GOE) indicates that significant environmental modifications were necessary for an effective accumulation of metabolically produced oxygen. Here we report a distinct temporal shift to heavier carbon isotope sig