The emergence of an aerobic world: isotopic evidence for biogeochemical changes at the Archean-Proterozoic transition
Zusammenfassung der Projektergebnisse
During the Archean-Proterozoic transition and the early Paleoproterozoic (between 2.6 and 1.9 billion years ago), Earth witnessed profound changes in the environmental conditions at the Earth surface that undoubtedly affected the evolution of life on this planet. Among these global perturbations was the first significant rise in atmospheric oxygen abundance (the so called Great Oxidation Event). Our understanding about this critical period in Earth history is largely based on geochemical and isotopic signals that were archived in sedimentary rock successions from that time. In particular, these changes in the environmental conditions that characterized Earth surface environments are discernible by studying the abundance and stable isotopic composition of selected redox sensitive elements (i.e., carbon, sulfur, iron). In addition to more frequently applied redox proxies, multiple sulfur isotope measurements were performed in order to specifically address changes in the atmospheric oxygen abundance. It was the aim of the research project “The emergence of an aerobic world: isotopic evidence for biogeochemical changes at the Archean-Proterozoic transition” to unravel part of this history by studying perturbations of the global sulfur cycle and relate these to the evolution of the global ocean-atmosphere system. In order to achieve this, fifteen holes were drilled under the auspices of the International Continental Scientific Drilling Program (ICDP) initiative FAR-DEEP (Fennoscandian Arctic Russia – Drilling Early Earth Project) in three different areas of the Fennoscandian Shield (northern Russia). Drill cores with a total length of 3650m were recovered that provide a unique and representative succession of rock samples across this critical time interval in Earth history. Multiple sulfur isotopes reveal a profound change in the operational mode of the global sulfur cycle. Prior to about 2.4 Ga, photochemical reactions of volcanogenic sulfur dioxide in an essentially oxygen-free atmosphere was the predominant source of sulfur for Earrh’s surface environments. In the aftermath of the Great Oxidation Event (i.e. <2.4 Ga), oxidative continental weathering supplied increasing quantities of dissolved sulfate to the ocean, stimulating microbial sulfur cycling in the sedimentary realm.
Projektbezogene Publikationen (Auswahl)
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(2012) Abundant Marine Calcium Sulphates – Radical Change of Seawater Sulphate Reservoir and Sulphur Cycle. In: Melezhik, V.A. et al. (Eds.) Reading the Archive of Earth’s Oxygenation. Volume 3: Global Events and the Fennoscandian Arctic Russia - Drilling Early Earth Project. Springer, p. 123-148
Strauss, H., Melezhik, V.A., Reuschel, M., Fallick, A.E., Lepland, A., Rychanchik, D.V.
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(2012) Insights into the sulfur cycle at 2.0 Ga agopreservation of sedimentary monosulfides and transient euxinia. Precambrian Research 196- 197: 193-203
Reuschel, M., Strauss, H., Melezhik, V.A.
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(2012) Isotopic evidence for a sizeable seawater sulfate reservoir at 2.1 Ga. Precambrian Research 192-195: 78-88
Reuschel, M., Melezhik, V.A., Whitehouse, M.J., Lepland, A., Fallick, A.E., Strauss, H.
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(2012) The End of Mass-Independent Fractionation of Sulphur Isotopes. In: Melezhik, V.A. et al.(Eds.) Reading the Archive of Earth’s Oxygenation. Volume 3: Global Events and the Fennoscandian Arctic Russia - Drilling Early Earth Project. Springer, p. 3-12
Reuschel, M., Strauss, H., Lepland, A., Prave, A.
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(2012) The Great Oxidation Event. In: Melezhik, V.A. et al. (Eds.) Reading the Archive of Earth’s Oxygenation. Volume 3: Global Events and the Fennoscandian Arctic Russia - Drilling Early Earth Project. Springer, p. 475-494
Kump, L.R., Fallick, A.E., Melezhik, V.A., Strauss, H., Lepland, A.
