摘要
东胜砂岩型铀矿床定位于灰绿色岩石与灰色岩石的接触部位,主要受古层间氧化带控制。矿体以板状为主。铀主要以铀矿物和吸附铀形式存在。铀矿物主要为铀石,UO2含量为46.72%～74.60%。吸附铀及U6+、U4+在铀矿床的不同地段所占比例存在明显差别。该铀矿床与世界上其他砂岩型铀矿床在成因上具有明显的不同,表现在矿床特征、岩石地球化学环境及控矿因素等方面具有很强的特殊性。晚侏罗世-早白垩世的构造热事件形成的含烃热流体参与了成矿作用,不仅为铀的活化、迁移、富集提供了有利条件,而且使铀矿床完全隐伏在还原环境中,对矿床的保存起到了重要作用。由烃类流体产生的后生还原作用所形成的灰绿色砂岩可作为铀矿床的岩石地球化学勘查标志。
Dongsheng sandstone-type uranium deposit is located at the contact zone of grayish green sandstones and gray sandstones in north Ordos Basin, which is controlled basically by paleo-interlayer oxidation zone. The uranium deposit is generally platy and uranium mainly exists as uranium-bearing minerals （coffinite etc. ） and adsorbed uranium, with UO2 contents of 46.72% -74. 60%. Proportions of the adsorbed uranium, U^＋6 and U^＋4 vary from section to section in this deposit. Based on the characteristics of ore deposit, lithogeochemical enviromnent and ore-controlling factor, the origin of the uranium deposit is different from that of other sandstone-type uranium deposit in the world. Hydrocarbons-containing heat fluid from Late Jurassic to Early Cretaceous tectono-thermal events participated in ore-forming processes. The heat fluid not only contributed to the activation, migration and enrichment of uranium, but also provided a reducing enviromnent for this uranium deposit, and played an important role in the conservancy of the deposit. The gray and grayish green sandstones formed by hysterogenic reduction can be used as the lithogeochemical markers for exploration of uranium deposit.
出处
《地球化学》
CAS
CSCD
北大核心
2007年第3期267-274,共8页
Geochimica
基金
国家计划铀矿地质项目(内蒙古东胜地区1:25万区域铀资源评价
No.200108)。
关键词
砂岩型铀矿床
岩石地球化学特征
烃类流体
东胜地区
鄂尔多斯盆地
sandstone-type uranium deposit
lithogeochemical characteristics
hydrocarbons-containing fluid
Dongsheng area
Ordos Basin
