Geological and geochemical features of wallrock alteration of surrounding ore mineralization in uranium deposit No.622

Based on the geological field and microscope observation of wallrock alteration of uranium deposit No.622 and field and microscope geochemical trace of major element and rare earth element, two main periods of hydrothermal actions closely related to mineralization have been classified. The first is alkali metasomatism and hematite type of uranium mineralization with middle enrichment of HREE caused by alkali hydrothermal action from the deeper magmatism and late mineralization. The second is acid hydrothermal action produced by near-surface circulating underground water which was mainly from atmosphere. This process brought about further fractionation of LREE and HREE high HREE concentration, and superimposition of fluorite-damourite type of Uranium metallogenesis. It is suggested that hematitization, fluoritization and damouritization phenomena which are widespread in the alternated metallogenic zone, the content increase of P2O5, MgO, TiO2, CaO, ΣREE and HREE, the decrease of SiO2, Na2O and the ratio of LREE/HREE, can be used as criteria for ore prospecting