The atmosphere and oceans became oxidized across two main transitional periods, the Great Oxidation Event (~2.45 and 2.2 Ga) and the Neoproterozoic Oxidation Event (~0.80 and 0.54 Ga). Pieces of evidence are found in South Africa, North America, Western Australia and Russia, but the real timing, duration, mechanism and range of O2 increase are still unsolved question due to poor age constraints and contradictory stratigraphic correlations between these different terrains. Intriguingly, several studies have emphasized a possible causal relationship between oxidation events, coeval global glaciation events and widespread activity of subaerial large igneous provinces.In Brazil, sedimentary rocks of the Paleoproterozoic Carajás and Quadrilatero Ferrifero Mineral Provinces, and the Neoproterozoic Jacadigo and Bambuí Groups were deposited during the Great and Neoproterozoic Events, respectively. Nevertheless, they are not considered in global reconstruction because of a still scanty geochronological, elemental and isotopic investigation. This imposes a deepened characterization. The aim of this project is, therefore: i) to constrain the timing of the Great and Neoproterozoic Oxidation Events, and associated glacial episodes through Re-Os geochronology of black shales and sedimentary sulphides of key sedimentary units from Brazil; ii) to perform Nd - Hf isotope systematics on the same organic-rich sediments, glacial diamictites and related carbonates from Brazil and their equivalent from Western Australia (Turee Creek Group) in order to characterize sediment sources and evaluate the potential role of Large Igneous Province in the oxygenation and global cooling of the Erath surface during the Proterozoic.
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