3.2 Ga detrital uraninite in the Witwatersrand Basin, South Africa: Evidence of a reducing Archean atmosphere
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Résumé
Research Article| February 02, 2018 3.2 Ga detrital uraninite in the Witwatersrand Basin, South Africa: Evidence of a reducing Archean atmosphere Ian Burron; Ian Burron 1Department of Geological Sciences, University of Manitoba, Winnipeg, R3T 2N2 MB, Canada Search for other works by this author on: GSW Google Scholar Giuliana da Costa; Giuliana da Costa 2Department of Geology, University of Johannesburg, P.O. Box 524, Auckland Park, 2006 Johannesburg, South Africa Search for other works by this author on: GSW Google Scholar Ryan Sharpe; Ryan Sharpe 1Department of Geological Sciences, University of Manitoba, Winnipeg, R3T 2N2 MB, Canada Search for other works by this author on: GSW Google Scholar Mostafa Fayek; Mostafa Fayek 1Department of Geological Sciences, University of Manitoba, Winnipeg, R3T 2N2 MB, Canada Search for other works by this author on: GSW Google Scholar Christoph Gauert; Christoph Gauert 3Department of Geology, University of the Free State, 9301 Bloemfontein, South Africa4Geological Survey of Saxony-Anhalt, 06118 Halle (Saale), Germany Search for other works by this author on: GSW Google Scholar Axel Hofmann Axel Hofmann 2Department of Geology, University of Johannesburg, P.O. Box 524, Auckland Park, 2006 Johannesburg, South Africa Search for other works by this author on: GSW Google Scholar Author and Article Information Ian Burron 1Department of Geological Sciences, University of Manitoba, Winnipeg, R3T 2N2 MB, Canada Giuliana da Costa 2Department of Geology, University of Johannesburg, P.O. Box 524, Auckland Park, 2006 Johannesburg, South Africa Ryan Sharpe 1Department of Geological Sciences, University of Manitoba, Winnipeg, R3T 2N2 MB, Canada Mostafa Fayek 1Department of Geological Sciences, University of Manitoba, Winnipeg, R3T 2N2 MB, Canada Christoph Gauert 3Department of Geology, University of the Free State, 9301 Bloemfontein, South Africa4Geological Survey of Saxony-Anhalt, 06118 Halle (Saale), Germany Axel Hofmann 2Department of Geology, University of Johannesburg, P.O. Box 524, Auckland Park, 2006 Johannesburg, South Africa Publisher: Geological Society of America Received: 04 Dec 2017 Revision Received: 05 Jan 2018 Accepted: 07 Jan 2018 First Online: 01 Feb 2018 Online Issn: 1943-2682 Print Issn: 0091-7613 © 2018 Geological Society of America Geology (2018) 46 (4): 295–298. https://doi.org/10.1130/G39957.1 Article history Received: 04 Dec 2017 Revision Received: 05 Jan 2018 Accepted: 07 Jan 2018 First Online: 01 Feb 2018 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Ian Burron, Giuliana da Costa, Ryan Sharpe, Mostafa Fayek, Christoph Gauert, Axel Hofmann; 3.2 Ga detrital uraninite in the Witwatersrand Basin, South Africa: Evidence of a reducing Archean atmosphere. Geology 2018;; 46 (4): 295–298. doi: https://doi.org/10.1130/G39957.1 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 evolution of oxygen levels in the Archean atmosphere is one of the most important questions in the study of early Earth environments. The presence of redox-sensitive uraninite in the Archean Witwatersrand Basin, South Africa, has been cited as evidence for a reducing Archean atmosphere; however, whether the uraninite is detrital or hydrothermal in origin has been intensely debated. Here, we present, for the first time, in situ U-Pb ages of uraninite from the Witwatersrand Basin that are significantly older than the host sedimentary rocks (the 3074 ± 6 Ma Dominion and 2872 ± 6 Ma Vaal Reefs). Uraninite grains from the Dominion Reef are 3186 ± 19 Ma and may have been eroded from 3174 ± 9 Ma granites in the immediate hinterland, while uraninite grains from the Vaal Reef formed at 2994 ± 48 Ma and 2918 ± 20 Ma and are similar in age to detrital zircon populations within the Central Rand Group, which includes the Vaal Reef. These predepositional ages conclusively prove the detrital origin of the uraninite and represent arguably the best evidence to date that the Mesoarchean atmosphere was more reducing than the modern atmosphere. The detrital origin of the uraninite strongly supports the modified paleoplacer model for uranium mineralization within the Witwatersrand Basin over the hydrothermal models. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,001 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,005 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».