Nitrogen isotope evidence for anoxic deep marine environments from the Mesoarchean Mosquito Creek Formation, Australia
| Autor: | Mark Barley, Roger Buick, Matthew C. Koehler |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
010504 meteorology & atmospheric sciences
Geochemistry Geology δ15N 010502 geochemistry & geophysics 01 natural sciences Anoxic waters Isotopes of nitrogen Sedimentary depositional environment Geochemistry and Petrology Isotopes of carbon Nitrogen fixation Ecosystem Nitrogen cycle 0105 earth and related environmental sciences |
| Zdroj: | Precambrian Research. 320:281-290 |
| ISSN: | 0301-9268 |
| DOI: | 10.1016/j.precamres.2018.11.008 |
| Popis: | Current evidence for oxygenated environments in the Mesoarchean is limited to the shallowest marine and fluvio-lacustrine settings. It is not until the Neoarchean that signs of oxygenated surface waters above outer shelf and basinal depositional environments become evident. In order to further explore the Mesoarchean redox landscape for signs of basinward surface water oxygenation, we present nitrogen and carbon isotope ratios from the turbiditic Mosquito Creek Formation of the Nullagine Group (∼2.9 Ga). The δ15N and δ13Corg values are invariant around −1.8‰ and −32‰ respectively throughout a 70 m section of drill-core, suggesting an ecosystem dominated by nitrogen fixers (anaerobic nitrogen cycling) and CO2 fixation by the Calvin Cycle. When compared with other Archean isotopic data, these results (i) provide further evidence that the Mosquito Creek Formation was deposited in a marine basin, and (ii) contain δ15N values that highlight the prevalence of nitrogen fixation by Mo-nitrogenase and the dearth of aerobic nitrogen metabolisms in the Mesoarchean. |
| Databáze: | OpenAIRE |
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