准噶尔盆地南缘楼庄子地区头屯河组下段砂体特征与铀成矿关系探讨  

Discussion on the Relationship Between Sand Body Characteristics and Uranium Mineralization in the Lower Member of Toutunhe Formation in Louzhuangzi Area,Southern Margin of Junggar Basin

作　　者：黄松 贾为卫 闫晶晶[1] HUANG Song;JIA Weiwei;YAN Jingjing(Geologic Party No.216,CNNC,Urumqi,Xinjiang 830011,China)

机构地区：[1]核工业二一六大队,新疆乌鲁木齐830011

出　　处：《铀矿地质》2023年第4期522-532,共11页Uranium Geology

基　　金：中国核工业地质局项目“新疆准噶尔盆地铀矿资源调查评价与勘查”(编号:202206)资助。

摘　　要：楼庄子地区是准噶尔盆地南缘砂岩型铀矿化的集中带之一,头屯河是其主要找矿目的层。文章以楼庄子地区头屯河组下段含矿砂体为研究对象,通过统计其厚度、含砂率和碎屑物含量、w(U)、w(Th)、w(C有)和w(S)值等数据,分析砂体的空间展布特征与铀矿体关系。结果认为:头屯河组下段含矿砂体属辫状河三角洲平原沉积,分支河道较发育,砂体分布稳定、连续且厚大,具备完整的“泥-砂-泥”结构,渗透性好,有利于成矿流体的迁移,为成矿提供了有利的流体运移通道和赋矿空间;矿体主要赋存于孔隙度高、渗透性好、富有机质的粗砂岩、砂砾岩中,砂体中泥岩夹层为0~2层时,成矿概率较大。通过综合分析认为砂体垂向岩性序列组合样式和平面展布形态共同决定了铀矿化类型及富集部位,砂体中有机质含量较高处有利于铀成矿,并且矿石品位与砂岩中有机质含量呈正相关。Louzhuangzi area is one of the concentrated belts of sandstone-type uranium mineralization in the southern margin of Junggar Basin,and Toutunhe Formation is the main prospecting target layer.In this article,the ore-bearing sand body of the lower member of Toutunhe Formation in Louzhuangzi area was studied in the way of the thickness,sand content rate and debris content,w(U),w(Th),w(C)and w(S)values and the analysis in the spatial distribution characteristics of sand bodies and the relationship between uranium ore bodies.The results showed that the ore-bearing sand bodies in the lower part of Toutunhe Formation belong to braided river delta plain deposits,with well-developed branch channels,stable,continuous and thick sand body,complete"mud-sand-mud"structure,and good permeability.It is conducive to the migration of ore-forming fluids,and can provide favorable fluid migration channels and ore-bearing spaces for ore-forming.Ore bodies mainly occurred in the coarse sandstone and glutenite with high porosity,good permeability,and rich in organic matter.When there are 0~2 layers of mudstone interlayer in the sand body,the probability of mineralization is relatively high.According to the comprehensive analysis,the vertical lithological sequence combination pattern and planar distribution form of the sand body jointly determine the uranium mineralization type and the enrichment location.The strong geochemical reduction barrier in the sand body is favorable for uranium ore-forming,and the ore body grade is closely related to the organic matter content in the sand body.

关 键 词：砂体展布 铀成矿 砂体厚度 楼庄子地区 

分 类 号：P619.14[天文地球—矿床学]