Ores of infiltration sandstone-hosted uranium deposits in the sedimentary cover are ubiquitous composed of dispersed soot powder mineralization of black,brownish-black colour.Longterm studies of such loose U-ores by a...Ores of infiltration sandstone-hosted uranium deposits in the sedimentary cover are ubiquitous composed of dispersed soot powder mineralization of black,brownish-black colour.Longterm studies of such loose U-ores by analytical transmission electron microscopy(ATEM)proved their polymineral nature.Uranium blacks are composed by at least three different U-mineral forms:oxide(uraninite),silicate(coffinite)and phosphate(ningyoite)which are present in various proportions of ore compositions.Such high dispersed friable uranium formations are difficult to diagnose by traditional mineralogical methods(optical,XRD,IR and X-ray spectroscopy,etc.)which analyze total sample composition(phases mixture);their results characterize the dominant sample phase,omitting both sharply subordinate and X-ray amorphous phases.All research results are based on ATEM methods(SAED+EDS),which are optimal for crystallochemical diagnostics in the mineralogical study of such uranium ores.The article presents the diagnostic characteristics under electron microscope(EM)of uranous minerals from different sandstone deposits with their origin being discussed.展开更多
基金financial support from the IGCP 675 of International Union of Geological Sciences(IUGS),UNESCO and China Geological Survey(Tianjin Center)。
文摘Ores of infiltration sandstone-hosted uranium deposits in the sedimentary cover are ubiquitous composed of dispersed soot powder mineralization of black,brownish-black colour.Longterm studies of such loose U-ores by analytical transmission electron microscopy(ATEM)proved their polymineral nature.Uranium blacks are composed by at least three different U-mineral forms:oxide(uraninite),silicate(coffinite)and phosphate(ningyoite)which are present in various proportions of ore compositions.Such high dispersed friable uranium formations are difficult to diagnose by traditional mineralogical methods(optical,XRD,IR and X-ray spectroscopy,etc.)which analyze total sample composition(phases mixture);their results characterize the dominant sample phase,omitting both sharply subordinate and X-ray amorphous phases.All research results are based on ATEM methods(SAED+EDS),which are optimal for crystallochemical diagnostics in the mineralogical study of such uranium ores.The article presents the diagnostic characteristics under electron microscope(EM)of uranous minerals from different sandstone deposits with their origin being discussed.
