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Author (up) Khoury, H.N.; salameh, E.M.; Clark, I.D. url  openurl
  Title Mineralogy and origin of surficial uranium deposits hosted in travertine and calcrete from central Jordan Type Journal Article
  Year 2014 Publication Applied Geochemistry Abbreviated Journal  
  Volume 43 Issue Pages 49-65  
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  Abstract Secondary uranium encrustations are hosted in thick travertine and calcrete deposits of Pleistocene–Recent age in central Jordan. The central Jordan varicolored marble and travertine are equivalent to the active metamorphic area in Maqarin, north Jordan. More than 100 samples were collected from the outcrops of the varicolored marble, travertine, calcrete, and the yellow uranium encrustations. The secondary yellow encrustations are mainly composed of uranyl vanadate complexes. Tyuyamunite Ca(UO2)2V25+O8·3(H2O)–strelkinite Na2(UO2)2V2O8·6(H2O) solid solution series are the major components and their composition reflects changes in the Ca/Na ratio in solution. Potentially, new vanadium free calcium uranate phases (restricted to the varicolored marble) were identified with CaO:UO3 ratios different from the known mineral vorlanite (CaU6+)O4. Carbon and oxygen isotope data from calcite in the varicolored marble are characterized by Rayleigh-type enrichment in light isotopes associated with release of 13C and 18O enriched CO2 by high temperature decarbonation during combustion of the bituminous marl. Stable isotope results from uranium hosted travertine and calcrete varieties exhibit a wide range in isotopic values, between decarbonated and normal sedimentary carbonate rocks. The depleted δ13C and δ18O values in the travertine are related to the kinetic reaction of atmospheric CO2 with hyperalkaline Ca(OH)2 water. The gradual enrichment of δ13C and δ18O values in the calcrete towards equilibrium with the surrounding environment is related to continuous evaporation during seasonal dry periods. Uranium mineralization in central Jordan resulted from the interplay of tectonic, climatic, hydrologic, and depositional events. The large distribution of surficial uranium occurrences hosted in travertine and calcrete deposits is related to the artesian ascending groundwater that formed extensive lakes along NNW–SSE trending depressions. Fresh groundwater moved upward through the highly fractured phosphate, bituminous marl and varicolored marble to form unusual highly alkaline water (hydroxide–sulfate type) enriched with sensitive redox elements among which were U and V.  
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  ISSN 0883-2927 ISBN Medium  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ khoury_mineralogy_2014 Serial 121  
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Author (up) Klaus, J.; Külls, C. openurl 
  Title Integrating residence time data in mixing cell modeling-Application to the Lower Kuiseb Dune area Type Conference Article
  Year 2009 Publication EGU Geophysical Abstracts Abbreviated Journal  
  Volume Issue Pages 11026  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ Klaus2009integrating Serial 54  
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Author (up) Klaus, J.; Külls, C.; Dahan, O. url  doi
openurl 
  Title Evaluating the recharge mechanism of the Lower Kuiseb Dune area using mixing cell modeling and residence time data Type Journal Article
  Year 2008 Publication Journal of Hydrology Abbreviated Journal  
  Volume 358 Issue 3-4 Pages 304-316  
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  Publisher Elsevier Place of Publication Editor  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ Klaus2008evaluating Serial 28  
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Author (up) Klaus, J.; Zehe, E.; Elsner, M.; Külls, C.; McDonnell, J.J. url  doi
openurl 
  Title Macropore flow of old water revisited: experimental insights from a tile-drained hillslope Type Journal Article
  Year 2013 Publication Hydrology and Earth System Sciences Abbreviated Journal  
  Volume 17 Issue 1 Pages 103  
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  Publisher Copernicus GmbH Place of Publication Editor  
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  Call Number THL @ christoph.kuells @ Klaus2013macropore Serial 23  
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Author (up) Klimkova, S.; Cernik, M.; Lacinova, L.; Filip, J.; Jancik, D.; Zboril, R. url  openurl
  Title Zero-valent iron nanoparticles in treatment of acid mine water from in situ uranium leaching Type Journal Article
  Year 2011 Publication Chemosphere Abbreviated Journal  
  Volume 82 Issue 8 Pages 1178-1184  
  Keywords Acid mine water, Contaminant removal, Surface stabilizing shell, Water treatment, Zero-valent iron nanoparticles  
  Abstract Acid mine water from in situ chemical leaching of uranium (Straz pod Ralskem, Czech Republic) was treated in laboratory scale experiments by zero-valent iron nanoparticles (nZVI). For the first time, nZVI were applied for the treatment of the real acid water system containing the miscellaneous mixture of pollutants, where the various removal mechanisms occur simultaneously. Toxicity of the treated saline acid water is caused by major contaminants represented by aluminum and sulphates in a high concentration, as well as by microcontaminants like As, Be, Cd, Cr, Cu, Ni, U, V, and Zn. Laboratory batch experiments proved a significant decrease in concentrations of all the monitored pollutants due to an increase in pH and a decrease in oxidation–reduction potential related to an application of nZVI. The assumed mechanisms of contaminants removal include precipitation of cations in a lower oxidation state, precipitation caused by a simple pH increase and co-precipitation with the formed iron oxyhydroxides. The possibility to control the reaction kinetics through the nature of the surface stabilizing shell (polymer vs. FeO nanolayer) is discussed as an important practical aspect.  
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  ISSN 0045-6535 ISBN Medium  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ klimkova_zero-valent_2011 Serial 196  
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