鄂尔多斯盆地北西部特拉敖包矿床铀矿石地球化学特征分析OA
Analysis of Lithogeochemical Features of Uranium Ore of Tela'aobao Deposit in Northwestern Ordos Basin
特拉敖包矿床是鄂尔多斯盆地北部下白垩统环河组首个特大型铀矿床,其铀矿石类型多样、成分复杂.为揭示不同类型铀矿石的成因联系与演化规律,文章通过光学显微镜、扫描电镜、电子探针、主微量元素分析等手段对特拉敖包矿床中多类型铀矿石的岩石学特征、铀矿物特征、地球化学组成进行分析.结果表明:铀矿石多埋深为 180～420 m,品位为 0.018 6%～0.175 5%;铀矿物以四方双锥状、针状或不规则状铀石为主,其次为钛-铁-铀混合物.主量元素组成整体相近,但TFe2O3 含量存在明显差异,其中紫色矿石中Fe含量最高,褐灰色、灰色矿石次之,褐绿色、绿褐色矿石最低,可作为划分矿石类型的标志性指标.微量元素中Zr、Zn、Cr、Pb、Ba相对富集.稀土元素分异特征显示,紫色及部分灰色、褐灰色矿石LREE/HREE值为0.28～3.72,表现为轻稀土亏损或弱富集;而绿褐色、褐绿色、褐灰色矿石LREE/HREE值为7.72～11.87,表现为轻稀土明显富集.Y在不同类型矿石中呈现规律性变化,指示其形成时氧化还原条件的差异.Co、Ni、V、Pb、Cu、Zn等元素与U呈明显相关性,且Cr表现出2种不同的变化趋势.综合岩石地球化学特征,认为特拉敖包铀矿床是由多期次的含矿流体以层间氧化带运移形式成矿,从而形成多类型铀矿石.
Tela'aobao deposit is the first super-large uranium deposit in Lower Cretaceous Huanhe Formation in the northern Ordos Basin,characterized by diverse uranium ore types and complex compositions.To reveal the genetic links and evolutionary patterns among different types of uranium ores,this study analyzed the petrological characteristics,uranium mineral features,and geochemical compositions of multiple uranium ore types from Tela'aobao deposit using optical microscopy,scanning electron microscopy,electron probe microanalysis,and major and trace element analysis.The results show that the uranium ores are predominantly buried at depths of 180-420 m,with grades ranging from 0.018 6%to 0.175 5%.Uranium minerals are mainly composed of tetragonal dipyramidal,acicular,or irregular coffinite,followed by Ti-Fe-U mixtures.The major element compositions are generally similar,but significant differences are observed in TFe2O3 contents,with purple ores having the highest Fe contents,followed by brownish-gray and gray ores,and brownish-green and greenish-brown ores having the lowest,which can serve as diagnostic indicators for ore type classification.Among trace elements,Zr,Zn,Cr,Pb,and Ba are relatively enriched.Rare earth element(REE)fractionation patterns show that purple and some gray and brownish-gray ores have LREE/HREE ratios of 0.28-3.72,indicating light REE depletion or weak enrichment,whereas greenish-brown,brownish-green,and brownish-gray ores have LREE/HREE ratios of 7.72-11.87,indicating significant light REE enrichment.Y shows systematic variations across different ore types,reflecting differences in redox conditions during their formation.Co,Ni,V,Pb,Cu,and Zn show significant correlations with U,while Cr exhibits two distinct trends.Based on the integrated petrogeochemical characteristics,it is concluded that the Tela'aobao uranium deposit was formed by multiple phases of ore-bearing fluids migrating as interlayer oxidation zones,resulting in the formation of multiple types of uranium ores.
姜晓杰;鲁超;王龙辉;张锋;狄彦宁
核工业二〇八大队,内蒙古 包头 014010核工业二〇八大队,内蒙古 包头 014010核工业二〇八大队,内蒙古 包头 014010核工业二〇八大队,内蒙古 包头 014010核工业二〇八大队,内蒙古 包头 014010
天文与地球科学
岩石地球化学铀矿石特拉敖包矿床鄂尔多斯盆地北西部
petrogeochemistryuranium oreTela'aobao depositnorthwestern Ordos Basin
《铀矿地质》 2026 (5)
763-776,14
中国核工业地质局地勘费项目"鄂尔多斯盆地北部鄂托克前旗—东胜地区铀矿资源调查评价与勘查"(编号:202201)内蒙古自治区"草原英才"项目"鄂尔多斯盆地北部铀资源成矿理论创新和铀矿大基地资源保障能力提升"联合资助
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