柴达木盆地西南缘古-新近系砂岩型铀矿化特征与成矿条件分析  

Characteristics and Metallogenic Conditions of Paleo-Neogene Sandstone-type Uranium Mineralization in the Southwestern Margin of Qaidam Basin

作　　者：王贵 陈擎 陈云杰 陈斌 邵恒博 WANG Gui;CHEN Qing;CHEN Yunjie;CHEN Bin;SHAO Hengbo(Research Institute No.203,CNNC,Xi’an,Shaanxi 710086,China)

机构地区：[1]核工业二〇三研究所,陕西西安710086

出　　处：《铀矿地质》2024年第6期1042-1052,共11页Uranium Geology

基　　金：中国核工业地质局项目(编号:202219、202219-1和202319-7)资助。

摘　　要：为了分析柴达木盆地西南缘古-新近系砂岩型铀成矿潜力,文章针对研究区的铀源条件、构造、沉积建造、水文地质、后生蚀变及铀矿化特征等进行研究后,认为区内古-新近系具有较好的砂岩型铀矿找矿前景。渐新统-上新统沉积期,柴达木盆地转为大型坳陷盆地阶段,盆地内发育河流、三角洲沉积体系,其中在西南缘发育有规模较大的辫状河道及扇状砂体,砂体厚度大,泥-砂-泥结构稳定,铀源丰富,补-径-排水动力体系发育完善;同时区内广泛发育的油气为铀成矿提供了充足的还原介质,增加了砂体的还原容量,形成了层间氧化-油气还原复成因的铀矿化。区内铀成矿作用大致可分为:古新世-中新世沉积成岩预富集阶段和上新世晚期以来的层间氧化-油气还原的铀成矿阶段。In order to analyze the metallogenic potential of sandstone type uranium deposit in Paleogene-Neogene in the southwestern margin of Qaidam Basin,the source conditions,structure,sedimentary formation,hydrogeology,epigenetic alteration and uranium mineralization characteristics in the study area were studied.It was concluded that Oligocene Lower Ganchaigou Formation,Miocene Upper Ganchaigou Formation,Lower Youshashan Formation,Pliocene Upper Youshashan Formation and Shizigou Formation are the main prospecting target layers for sandstone-type uranium deposits and with good prospecting prospects.During the Oligocene-Pliocene,the Qaidam area became a large-scale depression basin and developed river and delta sedimentary systems.Among them,large-scale braided channels and fanshaped sand bodies were formed in the southwestern margin.The sand body was thick,with stable mud-sand-mud structure,the uranium source was abundant,and the recharge-run off-discharge dynamic system was well developed.The reduction capacity of the sand body is favorable for the formation of infiltration-exudation composite uranium mineralization.The uranium mineralization in the area can be roughly divided into two stages:the Paleocene-Miocene pre-enrichment stage by sedimentary diagenesis and the infiltration-exudation composite genetic uranium metallogenic stage since the Late Pliocene.Genetically,uranium mineralization is of great potential in the southwestern margin of Qaidam Basin.

关 键 词：砂岩型铀矿 古-新近系 成矿条件 铀矿化特征 柴达木盆地 

分 类 号：P619.14[天文地球—矿床学]