Intermittent connectivity determines the oxygenation in the Favenc and lower Wilton packages of the greater McArthur Basin, northern Australia
Date
2025
Authors
Subarkah, D.
Blades, M.L.
Collins, A.S.
Farkaš, J.
Virgo, G.M.
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Australian Journal of Earth Sciences, 2025; 1-20
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D. Subarkah, M. L. Blades, A. S. Collins, J. Farkaš, G. M. Virgo
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Abstract
The oxygenation of the Earth’s surface and its role in the evolution of life on our planet remains an enigmatic debate. Estimates from conflicting studies suggest that the Proterozoic atmosphere may contain between 0.002 and 2 wt% oxygen. The stability of oxygen levels, their distribution in past atmospheres and oceans, and their drivers are also points of contention. Such questions become challenging to address because unmetamorphosed and well-dated Proterozoic sedimentary rocks that record these signatures are uncommon. To address this, we provide new carbonate geochemistry data from the Mesoproterozoic Dook Creek Formation and the Mainoru Formation in the greater McArthur Basin, northern Australia. The depositional window for these successions is constrained by U–Pb geochronology of detrital zircon and in situ carbonate U–Pb age mapping. Our geochemical data (Ce/Ce*) show that the ca 1.6–1.5 Ga units here record variable redox conditions up stratigraphy. Notably, the change in basin-water oxygen conditions appear to not have been induced by biological processes. The heterogeneity is instead interpreted to have been directly driven by the connectivity between the basin to the open ocean and improved circulation with oxic, marine shallow waters.
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© 2025 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The terms on which this article has been published allow the posting of the Accepted Manuscript in a repository by the author(s) or with their consent.