Abstract:

Nearly 30 uranium deposits found in Xiangshan orefield of Jiangxi Province, whose uranium mineralization are closely related to hypabyssal or super hypabyssal intrusive rock (subvolcanic rock). Whether porphyry or volcanic rock type is hydrothermal uranium deposits. Analyzing from the metallogenic tectonic characteristics of the hydrothermal deposits in the orefield, there are two kinds of uranium mineralization, namely, cryptoexplosion clastic rock type and alteration rock type, the latter mainly includes hydromica altered rock type and albitization altered rock type. In this paper, by collecting data, combining with the data of relevant topics, a comparative study of geochemical characteristics of various uranium mineralization was carried out. Results show that, the ore grade of cryptoexplosion clastic rock type is higher, and mostly content of U is more than 1%. There is lower SiO₂ and Na₂O and higher P₂O₅ , and the ratio of K₂O and Na₂O is 11.51 on average, and the main associated elements are Hf, Sb, Cu, Pb, Zn, Zr, etc.; K₂O/Na₂O of hydromica altered rock type is 4.83 on average, and associated elements are W, Pb, Mo, Th, Sb, etc.; K₂O/Na₂O of albitization altered rock type is 0.19 on average, U has a close relationship with CaO and P₂O₅, and associated elements are Sr, Zr and Hf, Sc, W, etc. From the albitization altered rock type, to hydromica altered rock type, to the cryptoexplosion clastic rock type, with the increasing of U grade, REE distribution curve appears a regular change from right to left lean.

Key words: cryptoexplosive clastic rock, uranium mineralization type, geochemistry, Xiangshan orefield, Jiangxi