四川盆地北部砂岩型铀矿岩石学特征及矿床成因研究  

Petrological characteristics and origin of the sandstone-type uranium deposits in the northern Sichuan Basin

作　　者：安国堡[1] 刘海博 冯永来[1] 辛存林[2] 蔡煜琦[3] 胡菊英 AN Guobao;LIU Haibo;FENG Yonglai;XIN Cunlin;CAI Yuqi;HU Juying(The 282 Team of Sichuan Nucleus Industrial Geology Bureau,Deyang 618000,Sichuan,China;College of Geography and Environmental Science,Northwest Normal University,Lanzhou 730070,Gansu,China;Beijing Research Institute of Uranium Geology,Beijing 100029,China;Faculty of Geomatics,Lanzhou Jiaotong University,Lanzhou 730071,Gansu,China)

机构地区：[1]四川省核工业地质局二八二大队,四川德阳6180002 [2]西北师范大学地理与环境科学学院,甘肃兰州730070 [3]核工业北京地质研究院,北京100029 [4]兰州交通大学测绘与地理信息学院,甘肃兰州730070

出　　处：《中国地质》2024年第3期881-897,共17页Geology in China

基　　金：四川省财政厅2017年省级事业单位政府购买服务试点项目“川东北铀矿、石墨矿远景调查”(川财综[2017]12号)资助。

摘　　要：【研究目的】铀资源是中国重要的战略资源和能源矿产,为更好地勘探和开发四川盆地北部砂岩型铀矿,有必要深入了解其地质特征和成矿模式。【研究方法】本文通过野外调查、岩矿鉴定和地球化学分析研究了砂岩型铀矿的岩石学特征,分析了其成矿过程。【研究结果】含矿主岩主要为下白垩统苍溪组钙质胶结中—细粒砂岩和砾岩。铀以自生铀矿物的形式存在,铀矿物主要为铀石,呈他形、半自形和自形柱状。【结论】米仓山铁船山组变质酸性火山岩和花岗岩为盆地砂岩型铀矿的形成提供了初始铀源。铀在水溶液中以碳酸铀酰离子的形式迁移,富含有机质和黄铁矿的沼泽和停滞水还原环境破坏了碳酸铀酰离子,使铀元素以沉积成岩为主局部叠加后生富集作用成矿。This paper is the result of mineral exploration engineering.[Objective]Uranium resources are China's important strategic resources and energy minerals.The thorough understanding of geological characteristics and metallogenic models of sandstone-type uranium deposits in the northern Sichuan Basin is to the benefit of exploration and development.[Methods]The petrological characteristics of sandstone-type uranium deposits are studied through field investigation,rock and mineral identification and geochemical analysis,and the mineralization process is analyzed.[Results]The ore-bearing rocks are mainly the calcareous cementation medium-fine-grained sandstone and conglomerate of the Lower Cretaceous Cangxi Formation.Uranium exists in the form of authigenic uranium minerals.Uranium minerals are mainly coffinite,which are in xenomorphic,euhedral and hypautomorphic granular.[Conclusions]The metamorphic acidic volcanic rocks and granites of the Tiechuanshan Formation in Micangshan provided the initial uranium source for the formation of sandstone-type uranium deposits in the basin.Uranium migrates in the form of carbonic acid containing uranyl ions in the aqueous solution.The reductive environment of swamps and stagnant water rich in organic matter and pyrite destroys the carbonic acid containing uranyl ions,causing uranium to precipitate and accumulate in the primary diagenesis stage and secondary epigenesis stage.

关 键 词：砂岩型铀矿 岩石学特征 成矿过程 矿产勘查工程 

分 类 号：P619.14[天文地球—矿床学]