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Author Ren, Y.; Yang, X.; Hu, X.; Wei, J.; Tang, C. url  openurl
  Title Mineralogical and geochemical evidence for biogenic uranium mineralization in northern Songliao Basin, NE China Type Journal Article
  Year 2022 Publication (down) Ore Geology Reviews Abbreviated Journal  
  Volume 141 Issue Pages 104556  
  Keywords Bacterial sulfate reduction, In-situ S isotope of pyrite, Northern Songliao basin, Sandstone-type uranium deposit, Sifangtai Formation  
  Abstract The sandstone-hosted uranium mineralization areas in the Sanzhao Sag of the northern Songliao Basin have been newly identified. The target stratum is the Upper Cretaceous Sifangtai Formation and the uranium mineralization mainly occurs in the bottom of Sifangtai Formation, corresponding to channel sand bodies in meandering river system, characterized by medium to fine-grained sandstone. This study proposes the uranium metallogenic model through petrographic observation, whole rock geochemistry, mineralogical study of uranium occurrence form (SEM), organic matter rock–eval pyrolysis analysis (REP) and in-situ sulfur isotope determination of different generations of pyrite by LA-MC-ICP-MS. Compared with the sandstones collected in barren reduction and oxidization zones, the mineralized sandstones show obvious increase in the contents of TOC, total sulfur, Y and U. Petrographic observations indicate that organic matters are mainly inherited from land plants. REP data display that the organic matter (OM) disseminated in the sandstone has very low hydrogen index (HI) from around 0 to 21 mg HC/g TOC and varied oxygen index (OI) from 44 to 115 mg CO2/g TOC, corresponding to Type Ⅳ kerogen (degraded kerogen). There are two types of coffinite with different grain size, micro-particles (μm-sized) and large aggregates (generally up to 100 μm) respectively. The coffinite micro spherules exhibit short rod-like or worm-like morphology occurring in clay matrix and cell cavities in degradofusinite or around subidiomorphic-idiomorphic pyrite. The coarse-grained coffinite contains other mineral facies (e.g. pyrite, quartz) and some of large coffinite aggregates display thrombolite-type microbial structures. The irregular pyrite relict particles in coarse-grained colloidal coffinite have light sulfur isotope compositions characterized by δ34S values from –39.96‰ to –49.89‰. The δ34S values of colloidal pyrite in replacement of OM or of the sub-idiomorphic FeS2 cement filling in the cavities of OM range from –52.77‰ to –13.88‰. Some of sub-idiomorphic pyrite cement and idiomorphic crystal have the heavier signature from – 27.06‰ to + 14.23‰. The light sulfur isotope signature suggests that the sulfur originates from bacterial sulfate reduction (BSR). The OM replacement by pyrite and the highest OI values recorded by REP in uranium mineralized samples are lines of evidence of biodegradation. Bacteria use the organic matter as food source and produce isotopically light reduced sulfur species. Oxygenated uranium-bearing waters infiltrated through the denudated windows at Daqing placanticline into the porous reduced sandstones deposited in the Sanzhao Sag. Uranium was indirectly reduced by BSR-derived iron disulfides or directly reduced by sulfate-reducing bacteria.  
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  ISSN 0169-1368 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number THL @ christoph.kuells @ ren_mineralogical_2022 Serial 144  
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Author Min, M.; Chen, J.; Wang, J.; Wei, G.; Fayek, M. url  openurl
  Title Mineral paragenesis and textures associated with sandstone-hosted roll-front uranium deposits, NW China Type Journal Article
  Year 2005 Publication (down) 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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  Notes Approved no  
  Call Number THL @ christoph.kuells @ min_mineral_2005 Serial 175  
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Author Rallakis, D.; Michels, R.; Cathelineau, M.; Parize, O.; Brouand, M. url  openurl
  Title Conditions for uranium biomineralization during the formation of the Zoovch Ovoo roll-front-type uranium deposit in East Gobi Basin, Mongolia Type Journal Article
  Year 2021 Publication (down) Ore Geology Reviews Abbreviated Journal  
  Volume 138 Issue Pages 104351  
  Keywords Bioreduction, East Gobi Basin, Mongolia, Organic matter, Roll-front, Sulfur isotopes, Uranium  
  Abstract The Zoovch Ovoo uranium roll-front-type deposit is hosted in the Sainshand Formation, a Late Cretaceous siliciclastic reservoir, which constitutes the upper part of the post-rift infilling of the Mesozoic East Gobi Basin in SE Mongolia. The Sainshand Formation consists of unconsolidated medium-grained sand, silt and clay intervals deposited in fluvial-lacustrine settings. The uranium deposit is confined within a 60–80 m thick siliciclastic sequence inside aquifer-driven systems. The overall system experienced shallow burial and was never subjected to temperatures higher than 40 °C. This study proposes a comprehensive metallogenic model for this uranium deposit. Sedimentological and mineralogical observations from drill core samples to the microscopic scale (optical and Scanning Electron Microscopy) together with in situ geochemistry of late-formed phases (Laser Ablation–Inductively Coupled Plasma Mass Spectrometry, Electron Probe Microanalysis, Fourier Transform–Infrared Spectroscopy) were considered for the reconstruction of the main stages of U trapping. In the mineralized zone, the uranium ore is expressed as Ca–enriched uraninite (UO2) and less commonly as Ca–enriched phospho-coffinite (U, P)SiO4. Trapping mechanisms include i) complexation (i.e. uranyl-carboxyl complexes), ii) adsorption on organic or clay particles) and iii) reduction by pyrite and by bacterial activity to amorphous uraninite. In all cases, the organic matter plays either the role of trap for uranium or nutrient for bacteria that can trap uranium through their metabolism. The shallow burial diagenesis conditions do not allow direct reduction of U(VI) by organic carbon. The δ34S values of the iron disulfide are very diverse, fluctuating in extreme cases between −50 to + 50‰, with an average δ34S value for framboidal pyrite at 2‰, and −20‰ for euhedral pyrite. The positive and negative values reflect close versus open fractionation systems, while bacterial sulphate reduction (BSR) is active during the whole diagenetic history of the deposit as an essential source of reduced sulfur. Therefore, using detrital organic matter as a carbon source, microorganisms play a significant role in uranium trapping, either as a direct reducing agent for uranium or pyrite formation, which will trap uranium through redox driven epigenetic processes.  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ rallakis_conditions_2021 Serial 176  
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Author Min, M.; Xu, H.; Chen, J.; Fayek, M. url  openurl
  Title Evidence of uranium biomineralization in sandstone-hosted roll-front uranium deposits, northwestern China Type Journal Article
  Year 2005 Publication (down) 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.  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ min_evidence_2005 Serial 186  
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Author Ardelt, G.; Külls, C.; Hellbrück, H. url  openurl
  Title Towards intrinsic molecular communication using isotopic isomerism Type Journal Article
  Year 2018 Publication (down) Open Journal of Internet Of Things (OJIOT) Abbreviated Journal  
  Volume 4 Issue 1 Pages 135-143  
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  Publisher RonPub Place of Publication Editor  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ Ardelt2018towards Serial 18  
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