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Author (up) Min, M.; Chen, J.; Wang, J.; Wei, G.; Fayek, M.
Title Mineral paragenesis and textures associated with sandstone-hosted roll-front uranium deposits, NW China Type Journal Article
Year 2005 Publication Ore Geology Reviews Abbreviated Journal
Volume 26 Issue 1 Pages 51-69
Keywords China, Mineralogy, Paragenesis, Sandstone-hosted roll-type uranium deposit
Abstract We present a first paragenetic study of the Wuyier, Wuyisan, Wuyiyi and Shihongtan sandstone-hosted roll-front uranium deposits, northwest China. The mineralization is hosted by Lower–Middle Jurassic coarse- to medium-grained sandstones, which are dark-gray to black due to a mixture of ore minerals and carbonaceous debris. The sandstone is alluvial fan-braided river facies. Minerals associated with these deposits can be broadly categorized as detrital, authigenic, and ore-stage mineralization. Ore minerals consist of uraninite and coffinite. This is the first noted occurrence of coffinite in this type of deposit in China. Sulfide minerals associated with the uranium minerals are pyrite, marcasite, and less commonly, sphalerite and galena. The sulfide minerals are largely in textural equilibrium with the uranium minerals. However, these sulfide minerals occasionally appear to predate, as well as postdate, the uranium minerals. This implies that there are multiple generations of sulfides associated with these deposits. The ore minerals occur interstitially between fossilized wood cells in the sandstones as well as replace fossilized wood and biotite. The deposits are generally low-grade. Primary uranium minerals associated with the low-grade deposits are generally too small, ranging from 0.2 to 0.3 μm in diameter, to be observed by optical microscopy and are only observed by electron microscopy. Mineral paragenesis and textures indicate that these deposits formed under low temperature (30–50 °C) conditions.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0169-1368 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ min_mineral_2005 Serial 175
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Author (up) Min, M.; Xu, H.; Chen, J.; Fayek, M.
Title Evidence of uranium biomineralization in sandstone-hosted roll-front uranium deposits, northwestern China Type Journal Article
Year 2005 Publication Ore Geology Reviews Abbreviated Journal
Volume 26 Issue 3 Pages 198-206
Keywords Biomineralization, China, Roll-front uranium deposit, Sandstone
Abstract We show evidence that the primary uranium minerals, uraninite and coffinite, from high-grade ore samples (U3O8\textgreater0.3%) in the Wuyiyi, Wuyier, and Wuyisan sandstone-hosted roll-front uranium deposits, Xinjiang, northwestern China were biogenically precipitated and psuedomorphically replace fungi and bacteria. Uranium (VI), which was the sole electron acceptor, was likely to have been enzymically reduced. Post-mortem accumulation of uranium may have also occurred through physio-chemical interaction between uranium and negatively-charged cellular sites, and inorganic adsorption or precipitation reactions. These results suggest that microorganisms may have played a key role in formation of the sandstone- or roll-type uranium deposits, which are among the most economically significant uranium deposits in the world.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0169-1368 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ min_evidence_2005 Serial 186
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