【摘要】 在深入研究砂岩型铀矿床层间氧化带各地球化学分带中铀及其伴生元素的分布规律时,发现一些单价态(不变价)元素也常常富集在层间氧化带前锋区,其典型代表是钪(Sc)、钇(Y)和稀土元素(REE)等。作者在综合分析前苏联众多砂岩型铀矿床各地球化学分带中各种元素大量测试数据的基础上,论述了层间氧化带前锋区Eh值和pH值的变化规律以及它们所导致的变价元素(U、Se、Mo和V)和不变价元素(Sc、Y和REE)的分布规律和富集机制。实际上,层间氧化带前锋区既是氧化-还原电位(Eh值)又是酸碱度(pH值)的急剧变化区,两者大致同步消长。层间氧化带前锋区有两类地球化学障:单纯的还原障和还原-碱性综合障。两种地球化学障的发育与强度取决于原始未氧化岩石中硫化物、有机质和碳酸盐的含量。更多还原

【Abstract】 During the detailed study on the distribution regularity of uranium element in various geochemical zones at interlayer oxidation type sandstone-hosted uranium deposits,it has been discovered that some univalent elements are often concentrated at redox front of interlayer oxidation zone.Sc,Y and REE are typical representatives of these univalent elements.On the basis of a comprehensive analysis of a great number analytic data of various elements in various geochemical zones at sandstone-hosted uranium deposits in the former Soviet Union,the authors expound the regular variation of Eh and pH values at the redox front area,as well as the regular distribution and concentration of both univalent(Sc,Y and REE)and multivalent(U,Se,Mo and V)elements.In fact,the redox front area is an area of rapid change for both oxidation-reduction potential(Eh value),and acidic-alkalic index of medium(pH value).The approximate synchronous increment and decrement of Eh and pH values represent the fundamental reason for the regular distribution and concentration of the above two-group elements.Actually,two kinds of geochemical barriers exist at redox front area:reducing barriers and comprehensive reducing-alkalic barrier.The development of the two-kind barrier and their intensity basically depends on how much sulphide,organic matter and carbonate material exist in initial unoxdized host rocks.更多还原