Dating the rise of atmospheric oxygen bekker

Other contributors were from the Geological Survey of Canada in Ottawa; Swedish Museum of Natural History; University of Johannesburg, South Africa; and the University of California-Riverside.

2.22 and 2.06 Ga, during the peak of the Lomagundi carbon isotope excursion.

The marbles, which are metamorphosed to upper amphibolite grade, show a wide spread of δ13Ccarb values, ranging from 11.3 to − 9.3‰ VPDB, and a range of δ18O values from − 9.9 to − 24.0‰ VPDB.

There is a generally positive correlation between δ13C and δ18O values in the marbles as well as between δ13C and Mn/Sr ratios.

Response of the redox state of the deep ocean to the rise of atmospheric oxygen, as well as the 2.22-2.1 Ga carbon isotope excursion that followed, is not known. 2.15 Ga Sengoma Argillite Formation (SAF), Botswana, is correlative with the Silverton Formation (SF), South Africa, which contains carbonates with delta °13°C values ranging from 8.3 to 11.3 0/00The Mbuji-Mayi Supergroup, deposited between 1170 ± 22 Ma and ca.

800 Ma [1], outcrops in the eastern Oriental Kasai Province and western Katanga Province of the Democratic Republic of Congo.

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The Paleoproterozoic Era witnessed crucial steps in the evolution of Earth's surface environments following the first appreciable rise of free atmospheric oxygen concentrations ∼2.3 to 2.1 Ga ago, and concomitant shallow ocean oxygenation.

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