Life on a Mesoarchean marine shelf – insights from the world’s oldest known granular iron formation

Abstract The Nconga Formation of the Mesoarchean (~2.96–2.84 Ga) Mozaan Group of the Pongola Supergroup of southern Africa contains the world’s oldest known granular iron formation. Three dimensional reconstructions of the granules using micro-focus X-ray computed tomography reveal that these granul...

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Autores principales:	Albertus J. B. Smith, Nicolas J. Beukes, Jens Gutzmer, Clark M. Johnson, Andrew D. Czaja, Noah Nhleko, Frikkie de Beer, Jakobus W. Hoffman, Stanley M. Awramik
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2020
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/a867a67a8d1d4168ac170697ece89de5
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spelling	oai:doaj.org-article:a867a67a8d1d4168ac170697ece89de52021-12-02T16:32:12ZLife on a Mesoarchean marine shelf – insights from the world’s oldest known granular iron formation10.1038/s41598-020-66805-02045-2322https://doaj.org/article/a867a67a8d1d4168ac170697ece89de52020-06-01T00:00:00Zhttps://doi.org/10.1038/s41598-020-66805-0https://doaj.org/toc/2045-2322Abstract The Nconga Formation of the Mesoarchean (~2.96–2.84 Ga) Mozaan Group of the Pongola Supergroup of southern Africa contains the world’s oldest known granular iron formation. Three dimensional reconstructions of the granules using micro-focus X-ray computed tomography reveal that these granules are microstromatolites coated by magnetite and calcite, and can therefore be classified as oncoids. The reconstructions also show damage to the granule coatings caused by sedimentary transport during formation of the granules and eventual deposition as density currents. The detailed, three dimensional morphology of the granules in conjunction with previously published geochemical and isotope data indicate a biogenic origin for iron precipitation around chert granules on the shallow shelf of one of the oldest supracratonic environments on Earth almost three billion years ago. It broadens our understanding of biologically-mediated iron precipitation during the Archean by illustrating that it took place on the shallow marine shelf coevally with deeper water, below-wave base iron precipitation in micritic iron formations.Albertus J. B. SmithNicolas J. BeukesJens GutzmerClark M. JohnsonAndrew D. CzajaNoah NhlekoFrikkie de BeerJakobus W. HoffmanStanley M. AwramikNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 10, Iss 1, Pp 1-8 (2020)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Albertus J. B. Smith Nicolas J. Beukes Jens Gutzmer Clark M. Johnson Andrew D. Czaja Noah Nhleko Frikkie de Beer Jakobus W. Hoffman Stanley M. Awramik Life on a Mesoarchean marine shelf – insights from the world’s oldest known granular iron formation
description	Abstract The Nconga Formation of the Mesoarchean (~2.96–2.84 Ga) Mozaan Group of the Pongola Supergroup of southern Africa contains the world’s oldest known granular iron formation. Three dimensional reconstructions of the granules using micro-focus X-ray computed tomography reveal that these granules are microstromatolites coated by magnetite and calcite, and can therefore be classified as oncoids. The reconstructions also show damage to the granule coatings caused by sedimentary transport during formation of the granules and eventual deposition as density currents. The detailed, three dimensional morphology of the granules in conjunction with previously published geochemical and isotope data indicate a biogenic origin for iron precipitation around chert granules on the shallow shelf of one of the oldest supracratonic environments on Earth almost three billion years ago. It broadens our understanding of biologically-mediated iron precipitation during the Archean by illustrating that it took place on the shallow marine shelf coevally with deeper water, below-wave base iron precipitation in micritic iron formations.
format	article
author	Albertus J. B. Smith Nicolas J. Beukes Jens Gutzmer Clark M. Johnson Andrew D. Czaja Noah Nhleko Frikkie de Beer Jakobus W. Hoffman Stanley M. Awramik
author_facet	Albertus J. B. Smith Nicolas J. Beukes Jens Gutzmer Clark M. Johnson Andrew D. Czaja Noah Nhleko Frikkie de Beer Jakobus W. Hoffman Stanley M. Awramik
author_sort	Albertus J. B. Smith
title	Life on a Mesoarchean marine shelf – insights from the world’s oldest known granular iron formation
title_short	Life on a Mesoarchean marine shelf – insights from the world’s oldest known granular iron formation
title_full	Life on a Mesoarchean marine shelf – insights from the world’s oldest known granular iron formation
title_fullStr	Life on a Mesoarchean marine shelf – insights from the world’s oldest known granular iron formation
title_full_unstemmed	Life on a Mesoarchean marine shelf – insights from the world’s oldest known granular iron formation
title_sort	life on a mesoarchean marine shelf – insights from the world’s oldest known granular iron formation
publisher	Nature Portfolio
publishDate	2020
url	https://doaj.org/article/a867a67a8d1d4168ac170697ece89de5
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Life on a Mesoarchean marine shelf – insights from the world’s oldest known granular iron formation

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