Dynamic interaction between basin redox and the biogeochemical nitrogen cycle in an unconventional Proterozoic petroleum system

Type Article
Date 2019-03
Language English
Author(s) Cox Grant M.1, Sansjofre Pierre2, Blades Morgan L.1, Farkas Juraj1, Collins Alan S.1
Affiliation(s) 1 : Univ Adelaide, Adelaide, SA 5005, Australia.
2 : Inst Univ Europeen Mer, Lab Geosci Ocean, UMR 6538, Rue Dumont dUrville, F-29280 Plouzane, France.
Source Scientific Reports (2045-2322) (Nature Publishing Group), 2019-03 , Vol. 9 , P. 5200 (11p.)
DOI 10.1038/s41598-019-40783-4
WOS© Times Cited 18

Precambrian hydrocarbons and their corresponding source rocks are distinctly different from their Phanerozoic counterparts, having been deposited in persistently anoxic environments in ecosystems dominated by bacteria. Here, we show that cyclic enrichment of organic matter in the world's oldest hydrocarbon play (ca. 1.38 Ga), is not associated with flooding surfaces and is unrelated to variations in mineralogy or changes in the relative rate of clastic to biogenic sedimentation-factors typically attributed to organic enrichment in Phanerozoic shales. Instead, the cyclic covariation of total organic carbon, delta N-15, delta C-13 and molybdenum are explained by the feedback between high levels of primary productivity, basin redox and the biogeochemical nitrogen cycle. These factors are important in constraining productivity in the marine biosphere, the development of Precambrian hydrocarbon source rocks, and more generally in understanding oxygenation of the ocean and atmosphere through Earth history; as all are ultimately related to organic carbon burial.

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