Abstract:

Dongsheng uranium deposit in Ordos basin is an important large sandstone-type uranium depositBy electronic microscopy, the thesis has made a detailed research on the uranium minerals category and output characteristicsIt has been identified that the main uranium minerals are coffinite and ursilite which are both epigenetic mineralThe diameters of uranium mineral's granule are very tiny, usually at micron (μm) level-Coffinite and ursilite are commonly tabular and irregularly granular, with an obvious phenomenon that is eroded on their surface, and some of them have eroded pore at nanometer (nm) degree; they are closely associated and have a close relationship with biotite and pyrite eroding. It can also be found that micro-vein uranium assemblages penetrate through the quartz clast.It has been researched that the uranium element is dissolved (transferred) and deposited (enriched) repetitively under the epigene.

Key words:  coffinite and ursilite, sandstone-type uranium deposit of Dongsheng, supergene uranium mineral, electronic microscopy, Ordos basin