吐哈盆地十红滩铀矿床北带西山窑组第二岩性段沉积体系对铀成矿的控制作用  

Sedimentary System of the Second Lithologic Member of Xishanyao Formation and Its Control on Uranium Mineralization in the North Belt of Shihongtan Uranium Deposit,Turpan-Hami Basin

作　　者：荆国强 伍群 王腾 JING Guoqiang;WU Qun;WANG Teng(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》2021年第6期1001-1012,共12页Uranium Geology

基　　金：中国核工业地质局项目(编号:201826-1)资助。

摘　　要：新疆吐哈盆地十红滩矿床是大型砂岩型铀矿床。文章以中侏罗统西山窑组为主要研究层位,通过岩性特征、沉积构造、沉积序列分析及连井剖面对比,研究第二岩性段沉积相特征及其对砂体展布和物性变化的控制,进而阐述西山窑组第二岩性段铀矿化发育的特征和控矿机理。研究认为,十红滩北带地区第二岩性段以辫状河三角洲前缘相沉积为主,沉积微相类型主要有水下分流河道、分流间湾,偶见河口砂坝。沉积微相对研究区铀矿化的影响主要体现在4个方面:具有可容空间的砂体连通性较好,河道变化处,沉积物粒度较粗,渗透性较好;水下分流河道是控制氧化带发育及矿体富集的主要微相,河道变化处或受构造影响的地段易成矿;沉积微相变化导致砂地比变化,矿化往往与泥质条带、钙质夹层或岩性变化面有关,与泥钙质层具有还原物质有关;砂体的物性变化影响矿体的宽度、厚度及富集程度。Shihongtan uranium deposit is a large sandstone type uranium deposit in Turpan-Hami basin,Xinjiang.This paper explained the development conditions and metallogenic mechanism of uranium mineralization in the second lithologic member of Xishanyao Formation in the Middle Jurassic by lithological characteristics,sedimentary structure and sedimentary sequence analysis,outcrop description and section contrast.It was believed that the second lithologic member in the north Shihongtan area are mainly the products of delta-front facies and can be divided micro-faces of distributary channel,distributary bay and estuary sandbar.There are four aspects of the influence of microfacies on uranium mineralization.First,the sand body with accommodation space has good connectivity,and the grain size is coarse and the permeability is good at the channel changes.Second,the underwater distributary channel is the main microfacies which control the development of oxidation zone and the enrichment of the ore bodies,and it is easy to form mineralization in the channel change area or the structural affected area.Third,the changing of microfacies controls sandstone percent,and mineralization is often associated with muddy strips,calcareous interlayers,lithologic change surfaces and reduction material in clay calcareous layers.The last,the physical properties of sand bodies affect the width,thickness and enrichment degree of ore bodies.

关 键 词：沉积微相 砂岩型铀矿 西山窑组 吐哈盆地 

分 类 号：P536[天文地球—古生物学与地层学] P619.14[天文地球—地质学]