贵州铜仁磷块岩型铀矿富含有机质,为探究有机质与P-U成矿关系,开展岩/矿石显微特征与地球化学测试研究。结果表明:有机质呈浸染状分布于胶磷矿中,与胶磷矿关系密切;矿石有机质质量分数较高,TOC均值为0.84%,与w(P2O5),w(U)均成一定的正相关关系;TOC/w(N)较低,w(Cr)/w(Zr)较高,指示矿石有机质与P,U来源相同,均以内源为主;高w(U)/w(Th)指示P-U成矿方式为热水沉积;低w(Th)/w(U)、高δw(U)和高w(V)/w(V+Ni)均指示磷块岩型铀矿形成于缺氧-硫化的还原环境。P-U成矿过程中,与P,U同源的有机质主要以吸附、生命组成和生成铀酰络合物等方式参与成矿物质的迁移活化,并通过释放还原性气体、形成腐殖酸和酸性铀酰络合物改变P-U成矿环境,促使P-U富集成矿。

The uranium-bearing phosphorite in Tongren,Guizhou is rich in organic matter. In order to ex‐plore the mineralization relationship between organic matter and P-U,microscopic characteristics of rock/ore and geochemical studies were carried out. The results showed that the organic matter was distributed in a leached form within the collophanite;The total organic matter content(TOC) in the ore was high,with an av‐erage value of 0. 84%. TOC exhibited a positive correlation with P2O5 and U contents. Moreover,low TOC/w(N) and high w(Cr)/w(Zr) ratios indicated that the organic matter in the ore and P-U were both of endog‐enous origin and high w(U)/w(Th) ratios implied that P-U might have enriched in hot waters,while low w（Th）/w（U） ratios，high δU values，and high w（V）/w（V+Ni） ratios indicated that the uranium-bearing phos‐ phorite might have been formed in a strong reduction environment. During P-U mineralization，organic mat‐ ter actively participated in the migration and activation of mineralized material mainly by adsorption，life  metabolism，and generation of uranyl complexes. These processes changed the P-U mineralized environment  by releasing reductive gas，forming humic acid and acidic uranyl complexes，which in turn contributed to PU enrichment and mineralization.