层间氧化带砂岩型铀矿床的铁物相特征及其地球化学意义——以伊犁盆地511铀矿床和吐哈盆地十红滩铀矿床为例

Characteristics and Geochemical Significance of the Ferrum Phases in the Shihongtan Interlayered-Oxidation Zone Sandstone Type Uranium Deposit

层间氧化带砂岩型铀矿床在空间上与层间氧化带各亚带的分布具有严格的对应关系。铁元素的物相特征是其所处地球化学环境变化的敏感标志。Fe_(Fe_2O_3)/TFe,Fe_((FeCO_3+FeS_2)/TFe,Fe_(Fe_2O_3)/Fe_((FeCO_3+FeS_2))等比值是反映地球化学环境变化的重要指标。应用铁物相特征及其以上比值,可以简捷地对层间氧化带进行亚带的划分,这对指导铀矿勘查具有重要理论和实践意义。过渡带中菱铁矿(FeCO_3)和黄铁矿(FeS_2)等对地球化学环境敏感的矿物的富集,指示了有利于铀成矿的中性—弱酸性、还原的地球化学环境。

The interlayered-oxidation zone sandstone type uranium deposits correspond spatially to the subzones of the interlayered-oxidation zone. The phases of ferrum are sensitive indicators of the geochemical environment changes. The FeFe2O3/Total Fe, Fe(FeCo3+FeS2)/Total Fe, FeFe2o3/Fe(Feco3+Fes2)Fe ratios are important parameters of the changes of the geochemical environment. Using the phases of ferrum and the parameters above to divide the subzones of interstratified-oxidation zone has both theoretical and practical significance in prospecting for u-ranium deposits of this type. The enrichment of minerals such as siderite and pyrite, which are sensitive to geochemical environment, in the transitional zone indicates that the geochemical environment is neutral-acidic and reductive and is propitious to the precipitation of uranium.