二连盆地恩格日音砂岩型铀矿床地质特征及成矿作用初探  

Geological Characteristics and Ore-forming Process of the Engeriyin Large Sandstone-type Uranium Deposit in the Manite Depression,Erlian Basin

作　　者：蒋喆 韩效忠 胡航 吴兆剑 李紫楠 来强 郭鹏 JIANG Zhe;HAN Xiaozhong;HU Hang;WU Zhaojian;LI Zinan;LAI Qiang;GUO Peng(Beijing Geological Survey Branch Company,China Coal Geology Group Co.,Ltd,Beijing 100040,China)

机构地区：[1]中煤地质集团有限公司北京地质调查分公司,北京100040

出　　处：《大地构造与成矿学》2020年第4期742-753,共12页Geotectonica et Metallogenia

基　　金：国家重点研发计划项目(2018YFC0604204);中国煤炭地质总局科技项目(ZMKJ-2018-18);中国地质调查局地质调查项目(DD20160127-03)联合资助。

摘　　要：恩格日音铀矿床是近年在二连盆地马尼特坳陷南缘新发现的一处大型砂岩型铀矿床。矿体在平面上呈近EW向展布,矿带长度超过7.6 km,宽度400~800 m,垂向上可分为三层,产状较平缓,主要赋存于下白垩统赛汉组冲积扇相及辫状河道相灰色粗砂岩、细砂岩、泥质砂砾岩中,呈层状、透镜状产出。矿石以低品位含铀碎屑岩型为主,铀主要以吸附态赋存于杂基中,其次以沥青铀矿和铀石形式存在。矿区主要蚀变类型包括黄铁矿化、褐铁矿化、绿泥石化、黏土化等,其中黄铁矿化与铀矿化关系密切。恩格日音铀矿床上部矿体成矿类型属于层间氧化带型,下部矿体形成时代为早白垩世晚期115.1±5.9 Ma,与赛汉组下段沉积时期接近,成矿类型属于沉积同生型,该结论深化了马尼特坳陷南缘铀成认识,拓宽了该区铀矿找矿方向。The Engeriyin deposit is a newly discovered large sandstone-type uranium deposit located in the southern Manite Depression of the Erlian Basin.The ore body is East-West elongated,extending more than 7.6 km with width of 400–800 m,and consists of three gently dipping ore bodies mainly occurring in the alluvial fan facies and braided channel facies of the Saihan Formation.The ores are mainly of low-grade clastic rock type found in grey sand stone and sandy conglomerate.Uranium in the ores mainly occurs as adsorptive uranium and less as uranium minerals such as pitchblende and coffinite.The alteration types include pyritization,ferritization,chloritization,and clayization.It should be mentioned that pyritization is closely related to uranium mineralization.The analytical results show that the upper orebody of the Engeriyin uranium deposit belongs to interlayer-oxidation zone type.The whole rock U-Pb isochron age of the lower orebody is 115.1±5.9 Ma,which indicates the deposit was formed in the late Early Cretaceous and belongs to sedimentary syngenetic type.

关 键 词：砂岩型铀矿 马尼特坳陷 成矿作用 层间氧化带型 沉积同生型 

分 类 号：P612[天文地球—矿床学]