Abstract:

Lijialing uranium deposit is a new uranium deposit of discovered in western Xiangshan in recent years. Hydrothermal alteration develops strongly and obvious alteration zoning phenomenon exists in this deposit. Based on detailed field and indoor petrography observation on the drilled well samples, this paper divided uranium mineralization period into center zone, near-ore alteration zone, near-ore alteration zone and far-ore alteration zone, of which the hydrothermal alteration intensity decreases gradually. Standardized Isocon graphic method shows that in the hydrothermal alteration zone, CaO, FeO, Fe₂O₃, Na₂O contents increase significantly, with accordance to the development of hematite, albitization and carbonatization facies. K₂O content decreases obviously, which is caused by that albite replace potash feldspar and then the K element is migrated from potash feldspar; while MnO and MgO display a characteristic of inversely proportional relationship, which shows that hydrothermal alteration metasomatic process is not only a kind of diffusion infiltration metasomatism, but also a kind of element migration pattern with convective equilibrium.The content changes of the trace elements such as Th, Y, Zr and Hf are consistent with those of uranium, indicating that those elements can be used for prospecting uranium mineralization. HREE contents are closely relative to the uranium mineralization. With enhancement of the alteration degree, the HREE contents increase more and more, which indicates that the oreforming fluid is rich in HREE, and is deeply derived.

Key words: normalized Isocon graphic method, hydrothermal alteration, Lijialing deposit, uranium ore