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A SHALLOW-BURIAL MINERALIZATION MODEL FOR THE UNCONFORMITY-RELATED URANIUM DEPOSITS IN THE ATHABASCA BASIN

2018; Volume: 113; Issue: 5 Linguagem: Inglês

10.5382/econgeo.2018.4588

1554-0774

Guoxiang Chi, Zhong Li, Haixia Chu, Kathryn M. Bethune, David Quirt, Patrick Ledru, Charles Normand, Colin Card, Sean Bosman, W J Davis, E G Potter,

Radioactive element chemistry and processing

Research Article| August 01, 2018 A SHALLOW-BURIAL MINERALIZATION MODEL FOR THE UNCONFORMITY-RELATED URANIUM DEPOSITS IN THE ATHABASCA BASIN G. Chi; G. Chi 1 Department of Geology, University of Regina, Regina, Saskatchewan S4S 0A2, Canada † Corresponding author: e-mail: guoxiang.chi@uregina.ca Search for other works by this author on: GSW Google Scholar Z. Li; Z. Li 1 Department of Geology, University of Regina, Regina, Saskatchewan S4S 0A2, Canada Search for other works by this author on: GSW Google Scholar H. Chu; H. Chu 1 Department of Geology, University of Regina, Regina, Saskatchewan S4S 0A2, Canada2 China University of Geosciences, Beijing 10083, China Search for other works by this author on: GSW Google Scholar K. M. Bethune; K. M. Bethune 1 Department of Geology, University of Regina, Regina, Saskatchewan S4S 0A2, Canada Search for other works by this author on: GSW Google Scholar D. H. Quirt; D. H. Quirt 3 Orano Canada Inc., Saskatoon, Saskatchewan S7K 3X5, Canada Search for other works by this author on: GSW Google Scholar P. Ledru; P. Ledru 3 Orano Canada Inc., Saskatoon, Saskatchewan S7K 3X5, Canada Search for other works by this author on: GSW Google Scholar C. Normand; C. Normand 4 Saskatchewan Geological Survey, Regina, Saskatchewan S4P 2C8, Canada Search for other works by this author on: GSW Google Scholar C. Card; C. Card 4 Saskatchewan Geological Survey, Regina, Saskatchewan S4P 2C8, Canada Search for other works by this author on: GSW Google Scholar S. Bosman; S. Bosman 4 Saskatchewan Geological Survey, Regina, Saskatchewan S4P 2C8, Canada Search for other works by this author on: GSW Google Scholar W. J. Davis; W. J. Davis 5 Geological Survey of Canada, Ottawa, Ontario K1A 0E8, Canada Search for other works by this author on: GSW Google Scholar E. G. Potter E. G. Potter 5 Geological Survey of Canada, Ottawa, Ontario K1A 0E8, Canada Search for other works by this author on: GSW Google Scholar Economic Geology (2018) 113 (5): 1209–1217. https://doi.org/10.5382/econgeo.2018.4588 Article history accepted: 12 May 2018 first online: 31 Jul 2018 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Tools Icon Tools Get Permissions Search Site Citation G. Chi, Z. Li, H. Chu, K. M. Bethune, D. H. Quirt, P. Ledru, C. Normand, C. Card, S. Bosman, W. J. Davis, E. G. Potter; A SHALLOW-BURIAL MINERALIZATION MODEL FOR THE UNCONFORMITY-RELATED URANIUM DEPOSITS IN THE ATHABASCA BASIN. Economic Geology 2018;; 113 (5): 1209–1217. doi: https://doi.org/10.5382/econgeo.2018.4588 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search nav search search input Search input auto suggest search filter All ContentBy SocietyEconomic Geology Search Advanced Search Abstract The unconformity-related U deposits associated with the Proterozoic Athabasca Basin are among the largest and richest U deposits in the world. The conventional genetic model suggests that mineralization occurred under deep-burial (>5 km), diagenetic-hydrothermal conditions at normal geothermal gradients (~35°C/km). Based on regional geochronostratigraphic and ore geochronological data, it is inferred that, at the time of primary U mineralization (≥ ca. 1540 Ma), the burial depths of the unconformity surface were likely <~3 km. The elevated fluid pressures (up to 1,500 bars) used to support the deep-burial model were probably overestimated due to misinterpretation of accidentally entrapped halite crystals as daughter minerals in fluid inclusions. The elevated fluid temperatures (180°–250°C) estimated from fluid inclusion and clay mineral geothermometry from both mineralized and barren areas, which were interpreted to have resulted from deep burial at normal geothermal gradients at the time of mineralization, may be alternatively explained by local or basin-scale elevation of geothermal gradients at the time of mineralization, followed by continued burial and/or temporarily increased thermal gradients after mineralization. The shallow-burial mineralization model can better explain the geologic characteristics of the unconformity-related U deposits, including development of pervasive clay alteration halos, breccia zones, and dissolution vugs locally filled with drusy quartz, as well as evidence of fluid boiling recorded by fluid inclusions. The modified model emphasizes the importance of combined basinal (development of brines) and deep-seated geodynamic factors for large-scale U mineralization. Recognition of these factors is important for U exploration in the Athabasca Basin and similar basins elsewhere. You do not currently have access to this article.