Redox state of the Archean atmosphere: Evidence from detrital heavy minerals in ca. 3250–2750 Ma sandstones from the Pilbara Craton, Australia 论文

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Research Article| February 01, 1999 Redox state of the Archean atmosphere: Evidence from detrital heavy minerals in ca. 3250–2750 Ma sandstones from the Pilbara Craton, Australia Birger Rasmussen; Birger Rasmussen 1Centre for Strategic Mineral Deposits, Department of Geology and Geophysics, University of Western Australia, Nedlands, WA 6907, Australia Search for other works by this author on: GSW Google Scholar Roger Buick Roger Buick 2School of Geosciences, Edgeworth David Building FO5, University of Sydney, Sydney, NSW 2006, Australia Search for other works by this author on: GSW Google Scholar Author and Article Information Birger Rasmussen 1Centre for Strategic Mineral Deposits, Department of Geology and Geophysics, University of Western Australia, Nedlands, WA 6907, Australia Roger Buick 2School of Geosciences, Edgeworth David Building FO5, University of Sydney, Sydney, NSW 2006, Australia Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1999) 27 (2): 115–118. https://doi.org/10.1130/0091-7613(1999)027<0115:RSOTAA>2.3.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Birger Rasmussen, Roger Buick; Redox state of the Archean atmosphere: Evidence from detrital heavy minerals in ca. 3250–2750 Ma sandstones from the Pilbara Craton, Australia. Geology 1999;; 27 (2): 115–118. doi: https://doi.org/10.1130/0091-7613(1999)027<0115:RSOTAA>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract The presence of detrital uraninite and pyrite in fluvial placers of the Witwatersrand basin, South Africa, has been used to infer low levels of atmospheric oxygen during the Archean (>2500 Ma). However, recent studies advocate a hydrothermal origin for these minerals, thereby limiting their value as constraints on the composition of the early atmosphere. In contrast, ca. 3250–2750 Ma fluvial siliciclastic sediments from the Pilbara Craton in Australia have never undergone significant hydrothermal alteration, and their heavy minerals are of unequivocal detrital origin. These heavy minerals include the redox-sensitive phases pyrite, uraninite, and gersdorffite, along with more inert zircon, rutile, chromite, and monazite. Locally, siderite is a major constituent (to 90%) of the heavy mineral population, with grains displaying evidence for several episodes of erosion, rounding, and subsequent authigenic overgrowth. Detrital siderite is very rare in post-Archean sandstones, largely due to its instability in oxidizing environments. However, its frequent survival of prolonged transport in well-mixed and therefore well-aerated Archean river waters that contained little organic matter strongly implies that the contemporary atmosphere was indeed much less oxidizing than at present. Moreover, concentrations of reduced sulfur species must have been very low in surface fluids for siderite to survive repeated transportation events without pyritization. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.