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| Asael, Dan; Rouxel, Olivier; Poulton, Simon W.; Lyons, Timothy W.; Bekker, Andrey. |
| The early Paleoproterozoic witnessed Earth's first major oxygenation, referred to as the Great Oxidation Event or GOE. The GOE began around 2.45 billion years ago (Ga) and progressed over hundreds of millions of years, as evidenced by multiple redox indicators, before coming to an abrupt end by ca. 2.06 Ga. The details of the GOE and the extent of oxygenation are still not resolved, however, and it is not dear how redox conditions across the GOE compare with those during the middle Proterozoic. In order to investigate the evolution of deep-ocean redox conditions during the GOE, we present Mo concentration and isotope data together with Fe speciation values for three key organic matter-rich shale units of the early Paleoproterozoic age (2.32-2.06 Ga). In... |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00442/55330/60642.pdf |
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| Matthews, Alan; Azrieli-tal, Irit; Benkovitz, Ayelet; Bar-matthews, Miryam; Vance, Derek; Poulton, Simon W.; Teutsch, Nadya; Almogi-labin, Ahuva; Archer, Corey. |
| Redox conditions and the mechanisms of redox development are a critical aspect of Eastern Mediterranean sapropels, whose formation in oxygen-depleted waters is closely related to water column stratification at times of global sea level rise and insolation maxima. Sapropels in the Nile Fan formed at relatively shallow water depths under the influence of the monsoon-driven freshwater output from the River Nile. This work evaluates the redox evolution of Holocene sapropel S1 in VALPAMED cruise core MD9509, recovered at 880 mbsl in the NE Nile Fan, using a combination of geochemical element proxies, Fe speciation, Fe and Mo isotopes studies. The productivity and redox proxies (Ba/Al, Mo/Al, U/Al, V/Al, Sb/Al) show well-defined enrichments in the sapropel, but... |
| Tipo: Text |
Palavras-chave: Nile Fan sapropel S1; Fe isotope fractionation; Fe speciation; Mo isotope fractionation; Anoxic non-sulphidic waters; Porewater pyrite diagenesis. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00409/52059/52762.pdf |
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