摘要
通过分析西宁盆地成矿区域地质、岩性岩相及构造环境演化,重点讨论了砂岩型铀矿化岩性岩相、构造、后生氧化作用及源区铀源特征。认为下元古界湟源群、蓟县系花石山群、基底发育的中酸性侵入岩、东部乐都北山岩体为成矿提供了铀源;研究区发育一套以河流相、三角洲相、滨浅湖相为主的杂色碎屑岩建造,砂体发育,局部夹有少量灰色岩层,是铀矿化发育的重要层位;由于后期构造对目的层的影响较弱,具备形成同生沉积叠加后生氧化改造的铀矿化,白垩纪早期形成的宽缓褶皱和各种正逆断层及白垩纪晚期的差异性升降运动形成的斜坡带为含铀含氧水提供了运移通道和富集场所,成矿有利位置为坳陷中部的扇前缘亚相。
By analyzing the regional geological background, feature of lithology and lithofacies and structural evolution of Xining basin, the characteristics of the lithology and lithofacies, structure, epigenetic oxidation and source of uranium for sandstone-type uranium mineralization were discussed mainly. Lower Proterozoic Huangyuan Group and Jixian System Huasbishan Group, acidic intrusive rocks in the basement and Beishan rock in eastern Ledu were considered to provide source for uranium mineralization. The sand bodies and some gray rocks developed, which motley sedimentary rock of the fluvial facies, delta facies and shallow lake facies in Xining basin were the important horizon for uranium mineralization. Due to the weak influence of late tectonic action on the target layer, this basin bears the condition of uranium mineralization by the syngenetic sedimentation and epigenetic modification. Wide gentle folds formed in Lower Cretaceous and slope belt formed by differential lifting movement normal and reverse faults in Upper Cretaceous provided transport channel and enrichment sites for water with oxygen and uranium. The fan front subfacies of cetral depression were mineraliztion favorable position.
出处
《世界核地质科学》
CAS
2017年第2期70-79,共10页
World Nuclear Geoscience
基金
中国核工业地质局(编号:201149)
中国地质调查局(编号:1212011140125)铀矿评价项目资助
关键词
砂岩型铀矿
地质特征
西宁盆地
sandstone-type uranium deposit
geological characteristics
Xining basin
