层间氧化作用下分散元素独立成矿的可能性

研究了伊犁盆地扎基斯坦砂岩型铀矿床中的分散元素(Re、Se)超常富集现象,探讨了分散元素在层间氧化带独立成矿的可能性。表生环境下分散元素活化迁移、吸附或还原沉淀的地球化学条件,以及分散元素在砂岩铀矿床中超常富集的独立性研究表明,(1)干旱、半干旱等表生条件下,分散元素可以被含氧地表水从蚀源区岩石中汲取、活化并迁移;(2)层间氧化带之氧化-还原过渡带可以形成导致溶解于水的分散元素被吸附固定或还原沉淀所需的地球化学障条件;(3)砂岩铀矿床中的分散元素超常或异常富集具有相对独立性。指出在具备矿源条件下,分散元素(Re、Se、Ga、Ge等)在层间氧化带砂岩中超常富集并独立成矿是可能的。建议加强表生环境下分散元素的基础成矿理论系统研究。

Possibility of the Independent Mineralization of the Dispersed Elements(e.g.Re,Se)Under Interlayer Oxidation

This paper has reported the discovery that the dispersed elements(Re,Se) are extremely enriched in the Zhajistan sandstone-hosted uranium deposit,Yili Basin,discussed the possibility of the independent mineralization of the dispersed elements under interlayer oxidation.The analysis on aspects of geochemical conditions such as the activation,migration,adsorption or reduced precipitation of the dispersed elements in surficial circumstance,and on independence of the abnormal enrichment of the dispersed elements in the sandstone-hosted uranium orebody has indicates that,(1) the dispersed elements contained in source rocks could be activated and migrated by surface water under arid and semi-arid climate;(2) the geochemical barrier which is needed for adsorption or reduced precipitation of the dispersed elements dissolved in groundwater could be formed in the interlayer oxidation zone,(3) the abnormal enrichment of the dispersed elements in sandstone-hosted uranium orebody is relatively independent.Thus it is believed that the dispersed elements(e.g.Re,Se,Ga,Ge) could be abnormally enriched to form independent mineralization in redox sub-zone of the interlayer oxidation zone in the precondition of the existence of metallogenetic source beds.It is suggested that the systematic research on the fundamental metallogenic theory on the mineralization of the dispersed elements in surface should be undertaken further.