鄂尔多斯盆地北部直罗组黄铁矿与砂岩型铀矿化关系研究  

The Relationship Between Pyrite and Sandstone-hosted Uranium Mineralization of the Zhiluo Formation in the Northern Ordos Basin

作　　者：陈超[1] 刘洪军[2] 侯惠群[1] 韩绍阳[1] 柯丹[2] 白云生[1] 欧光习[2] 李言瑞 

机构地区：[1]中国核科技信息与经济研究院,北京100048 [2]核工业北京地质研究院中核集团铀资源勘查与评价技术重点实验室,北京100029

出　　处：《地质学报》2016年第12期3375-3380,共6页Acta Geologica Sinica

基　　金：国家重点基础研究发展计划(973计划)项目(编号2015CB453003)资助成果

摘　　要：鄂尔多斯盆地东北部是我国砂岩型铀矿重要成矿区。通过对盆地北部大营铀矿床直罗组赋矿地层砂岩野外观察、镜下鉴定发现,黄铁矿存在多种产状,它们的宏观、镜下产状存在一定对应关系。对黄铁矿硫同位素的分析测试以及蚀变矿物的研究发现,δ^(34)S的变化范围-36.5‰^-27.3‰,平均值为-32.28‰,为较小的负值,具有明显生物成因作用。同时草莓状黄铁矿以及生物碎屑胞腔中的铀矿物的发现,也证实了铀成矿期的生物作用。地下水中U^(6+)、Fe^(2+)与"轻"的H_2^(32)S发生氧化还原反应,从而形成了黄铁矿与铀矿的紧密伴生的现象。The northeastern Ordos basin is an important metallogenic area for sandstone type uranium deposits in China. Field observation and microscopic identification for the Zhiluo Formation orebearing strata in the Daying uranium deposit suggest that pyrite occurs as several form and there is a certain correspondence relation between their macroscopic and microscopic occurrence. Sulfur isotope analysis of pyrite and study of alteration minerals indicate that δ4S values vary from -36.5‰ to -27.3‰, with an average of -32.28‰, suggesting an obvious biogenic process. Meanwhile, the discovery of framboidal pyrite and uranium minerals in biological debris cells also confirms biological effects on uranium mineralization. U6＋ and Fe2 ＋ reacted with light H2 32S in the groundwater, resulting in the paragenesis of pyrite closely and uranium mineralization.

关 键 词：砂岩型铀矿 黄铁矿 硫同位素 蚀变 大营 鄂尔多斯盆地 

分 类 号：P619.14[天文地球—矿床学]