贵州松林铀多金属磷块岩微量元素地球化学及Sm-Nd同位素特征

Characteristics of trace element geochemistry and Sm-Nd isotope in uraniferous polymetallic phosphorite of Songlin,Guizhou province

贵州省遵义松林地区下寒武统牛蹄塘组磷块岩富集铀及多金属元素。以松林地区非常规铀资源为主要研究对象,在松林剖面系统取样的基础上,进行微量元素和Sm-Nd同位素测定。分析结果表明,该区铀多金属磷块岩主要富集U、Mo、Ni、Re、Tl等亲硫元素及过渡元素,U与Mo、Ni、Re、Tl具有良好的正相关关系;V/Cr>2、Ni/Co>4和δU>1的比值特征指示该区形成于缺氧的沉积环境;铀多金属磷块岩U-Th关系图解显示其受热水沉积作用影响;铀多金属磷块岩Sm-Nd同位素参数及Nd模式年龄数据显示其物质来源具有壳源特征。研究认为,松林地区非常规铀资源受热水沉积作用影响,在缺氧的沉积环境下深部热水活动为铀多金属磷块岩的形成提供丰富的物质来源。

The phosphorite at the bottom of Lower Cambrian in Songlin of Zunyi, Guizhou province is rich in uranium and metal elements. The trace elements and Sm-Nd isotopic analysis were used to study the uraniferous polymetallic phosphorite based on the systematic sampling along Songlin section. The sulfophilic elements of U, Mo, Ni, Re, Tl and transition elements were enriched in the uraniferous polymetallic phosphorite. The element of U has a good positive correlation with Mo, Ni, Re, Tl. The characteristics of V/Cr〉2, Ni/Co〉4, δU〉I and the diagram of U-Th indicated that the uraniferous polymetallic phosphatrite formed in the anoxic environment and affected by the hot water deposition. The Sm-Nd isotopic characteristics and Nd model ages revealed that the material source was related to crust. It was suggested that the unconventional uranium resource in $onglin was affected by hot water deposition, and the activity of deep hot water provided various metal elements for the forming of uraniferous polymetallic phosphate in the anoxic sedimentary environment.