世界核地质科学2023，Vol.40Issue(4)：908-923,16.DOI:10.3969/j.issn.1672-0636.2023.04.003
鄂尔多斯盆地巴音青格利铀矿床地球化学特征及其对铀成矿的指示意义
Analysis of the Geochemical Environment and its Indicative Significance for Uranium Mineralization in Bayinqinggeli Uranium Deposit,Ordos Basin
摘要
Abstract
Limited research was reported on the Bayinqinggeli uranium deposit.This article made a systematic sampling of the sandstone in the target layer of the Bayinqinggeli uranium deposit,and devided the samples according to green secondary reduction zone,red mineralization zone,and gray reduction zone for analysis.Based on the superposition metallogenic model proposed by predecessors,a detailed element analysis of the geochemical composition of various types of sandstones were conducted by the results of X-ray diffraction.By combining scanning electron microscopy observations and element analysis,the correlation between various minerals was established.The X-ray diffraction analysis results show that the sandstone of Bayinqinggeli uranium deposit is mainly composed of quartz,the green sandstone in the secondary reduction zone bears the characteristics of feldspar dissolution and rich clay minerals,the ore-hosting sandstone and gray sandstone are composed of more calcite cementation and more pyrite.The clay minerals in different sandstone zones are mainly composed of smectite.Gray sandstone and ore-hosting sandstone are with more kaolinite,which is similar to that of the Daying and Nalinggou uranium deposits.Through analysis,it was believed that the alteration during the diagenetic stage and the early interlayer oxidation stage,the parent rock mineral was altered to kaolinite by acidic fluids,in the later interlayer oxidation stage,and a large amount of kaolinite is converted to smectite due to alkaline.Final in the secondary reduction stage,smectite was partially transformed into chlorite and illite due to the influence of high-temperature alkaline fluid seeping out.The composition characteristics of major elements show a significant increase in TFe in ore-hosting sandstone,which is believed to be related to the Fe adsorption through formation of pyrite.At the same time,Fe3+/Fe2+of ore-hosting sandstone is higher,while both green and gray sandstones are lower;S,TOC and uranium mineralization are closely related.Through scanning electron microscopy,uranium minerals were observed closely related to smectite,pyrite,calcite,and organic matter.During the mineralization period,sulfate reducing bacteria in the organic matter reduced SO42-in the fluid to H2S,forming a strong local reducing environment.Fe,S,and U adsorbed in the organic carbon are co-deposited and cemented by calcite at the same time,and avoiding the transformation of secondary reduction in the later stage.Green sandstone and gray sandstone underwent a transformation from Fe3+to Fe2+and form chlorite during the secondary reduction stage.The comprehensive analysis shows that the Bayinqinggeli uranium deposit formed from diagenetic stage,early interlayer oxidation stage,late interlayer oxidation stage and secondary reduction stage successively by reducing acid coalbed methane,acidic oxidation infiltration water,alkaline oxidation infiltration water and reducing alkaline hydrocarbon fluids,resulting in complex environmental changes of Zhiluo formation.关键词
直罗组/地球化学/铀成矿/巴音青格利铀矿床/鄂尔多斯盆地Key words
Ordos basin/Bayinqinggeli uranium deposit/Zhiluo formation/geochemistry/uranium mineralization分类
天文与地球科学引用本文复制引用
刘威宏,刘红旭,丁波,任志勇..鄂尔多斯盆地巴音青格利铀矿床地球化学特征及其对铀成矿的指示意义[J].世界核地质科学,2023,40(4):908-923,16.基金项目
中国核工业地质局地质科技项目"北方中新生代盆地砂岩铀矿新一轮战略选区"(编号:地D2204) （编号:地D2204）
"铀矿重点勘查区成果进展跟踪与动态评价及勘查部署建议"(编号:地D2219) （编号:地D2219）
"甘蒙地区砂岩型铀矿综合编图与选区"(编号:地D2109) （编号:地D2109）
中核集团"青年英才"科研项目(编号:QNYC2103)联合资助. （编号:QNYC2103）
