U-Blacks Mineralization in Sandstone Uranium Deposits  

作　　者：Olga A.Doynikova 

机构地区：[1]Institute of Ore Deposits Geology,Petrography,Mineralogy and Geochemistry Russian Academy of Science,Moscow 119017,Russia

出　　处：《Journal of Earth Science》2022年第2期308-316,共9页地球科学学刊（英文版）

基　　金：financial support from the IGCP 675 of International Union of Geological Sciences(IUGS),UNESCO and China Geological Survey(Tianjin Center)。

摘　　要：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.

关 键 词：uranous minerals URANINITE COFFINITE ningyoite biogenic nature U-deposit ore deposit geology 

分 类 号：P619.14[天文地球—矿床学]