摘要
砂岩型铀矿床是一种具有重要经济价值的铀矿类型,受到世界各国地质勘探部门的高度关注。本文应用电子探针和高分辨分析型电镜联合研究鄂尔多斯盆地砂岩型铀矿铀的赋存状态;对砂岩中铀、钍及稀土含量的分布进行了线扫描分析,观察到铀矿物微粒主要分布在砂岩的主要造岩矿物裂隙中及其胶结物中。铀矿物主要存在形式是以铀石微粒(UO2)的形式存在,以微粒吸附形式存在(小于1μm)。铀石微粒一般富集在砂岩中的钾长石、微斜长石、白云母裂隙和解理缝或胶结物中,分析数据显示氧化铀的含量可达1%～3.46%,在石英和方解石颗粒裂隙或解理缝中比较低。应用高分辨的电镜还观察到少数呈较大铀石微粒集合体形式存在,最大可达200μm。从电子探针分析数据上看,UO2含量可以从0至几个百分含量,一般来说含铀高的部位,其对应的稀土元素、ThO2含量也较高。本文的研究对含油气盆地的铀矿质的沉淀、运移和富集的认识具有重要意义,同时对鄂尔多斯盆地铀矿开发过程的选冶工艺的确定,具有借鉴价值。
Sandstone-type uranium deposits, which have important industrial value, have drawn worldwide attentions. This paper studies mainly uranium mineral occurrence of sandstone-type uranium deposits in the Ordos basin using high-resolution SEM and EPMA. U-bearing minerals were observed to occur and be enriched mainly in cracks or cleavages of potassic feldspar, microcline and muscovite and cement in the form of very tiny grains （〈1μm）. The minerals are dominated by UO2 grains. Analytic data show that the content of UO2 can reach to 1%-3.46%, with lowest contents in cracks or cleavages of quartz and calcite grains. EPMA also shows that minor U-bearing minerals occur as aggregates with the largest ones up to -200μm. Analytical data indicate that UO2 Contents range from 0 to 3.46%. Generally, high-U bearing minerals are also high in the contents of Th and REE. This study is not only of great significance to understanding of uranium migration, sedimentation and enrichment coexisting with oil and natural gases in sedimentary basins, but also of referential significance to the utilization and metallurgic technology of sand-type U resources in the Ordos basin.
出处
《地质学报》
EI
CAS
CSCD
北大核心
2009年第8期1167-1177,共11页
Acta Geologica Sinica
基金
国家科技部"973"项目"多种能源矿产共存成藏(矿)机理与富集分布规律"(编号2003CB214606)
国家大学生创新性实验计划及中国地质大学地质过程与矿产资源重点实验室资助项目(编号GPMR0506)联合资助成果
