和什托洛盖盆地西南缘中侏罗统铀成矿条件分析

Analysis of Uranium Metallogenic Conditions of Middle Jurasic in the Southwest Margin of Heshituoluogai Basin

为查明和什托洛盖盆地西南缘中侏罗统头屯河组砂岩型铀矿化与铀成矿条件关系,进一步扩大找矿成果。通过对构造、地层、水文地质、铀源、古气候及后生蚀变等铀成矿条件分析,厘定和什托洛盖盆地西南缘铀矿化控制因素,综合分析中侏罗统砂岩型铀矿找矿前景。什托洛盖盆地西南缘晚侏罗世抬升剥蚀阶段为铀成矿有利阶段,南部斜坡带为有利构造部位。中侏罗统头屯河组为主要含矿目的层位,埋深较浅,沉积相类型以辫状河、辫状河三角洲为主。盆地西南缘铀成矿控制因素主要包括构造与古气候、岩相-岩性、后生蚀变和铀源。西南缘斜坡带具相对稳定的大地构造背景、有利砂体及丰富铀源,砂体中含有较多有机质和黄铁矿等还原剂,具完善的地下水“补-径-排”体系,发育层间氧化带和还原带,具有较好的砂岩型铀矿成矿潜力和找矿前景。

In order to find out the relationship between sandstone-type uranium mineralization and uranium metallogen-ic conditions of Toutunhe Formation of Middle Jurassic in the southwestern margin of Heshitologai Basin,and further ex-pand the prospecting results.Through the analysis of uranium metallogenic conditions such as structure,stratum,hydro-geology,uranium source,paleoclimate and epigenetic alteration,the controlling factors of uranium mineralization in the southwestern margin of Heshituoluogai Basin are determined,and the prospecting prospect of sandstone-type uranium deposits in the Middle Jurassic is comprehensively analyzed.The southwestern margin of Shituoluoguai basin was favor-able for uranium mineralization in the uplift and denudation stage of Late Jurassic,and the southern slope belt was the fa-vorable structural position.The Middle Jurassic Toutunhe Formation is the main ore-bearing target horizon with shallow burial depth.The sedimentary facies types are mainly braided river and braided river delta.The controlling factors of ura-nium mineralization in the southwestern margin of the basin mainly include structure and paleoclimate,lithology-litholo-gy,epigenetic alteration and uranium source factors.The slope belt in the southwestern margin has relatively stable tec-tonic background,favorable sand bodies and abundant uranium sources.Sand bodies contain more organic matter and py-rite and other reducing agents.It has a perfect groundwater recharge-runoff-excretion system,and develops interlayer oxi-dation zone and reduction zone.It has good metallogenic potential and prospecting prospect of sandstone-type uranium deposits.