准噶尔盆地南缘楼庄子地区头屯河组下段赋铀砂岩地球化学特征及地质意义  

Geochemical characteristics and geological significance of uraniumbearing sandstone in the lower member of Toutunhe formation in Louzhuangzi area,southern margin of Junggar basin

作　　者：郭超 贾为卫 黄松 王国荣[1] 廉刚 GUO Chao;JIA Weiwei;HUANG Song;WANG Guorong;LIAN Gang(Geologic Party No.216,CNNC,Urumqi 830011,China)

机构地区：[1]核工业二一六大队,新疆乌鲁木齐830011

出　　处：《世界核地质科学》2025年第1期45-59,共15页World Nuclear Geoscience

基　　金：中国核工业地质局铀矿调查评价项目“新疆准噶尔盆地南缘金沟河-浅水河地区铀矿资源调查评价(编号:202107-2)”资助。

摘　　要：通过地球化学分析、镜下鉴定和岩心观察等方法,分析楼庄子地区头屯河组下段赋铀砂岩的岩石学特征、地球化学特征、物源组成、构造背景及沉积环境,初步探讨其与铀成矿的关系。结果显示:头屯河组下段含矿砂岩源岩形成构造背景主要为活动大陆边缘和被动大陆边缘,特殊的构造背景为铀的迁移提供有利条件,同时也造就物源的多源性;砂岩碎屑物源以中性火成岩为主,母岩主要为花岗岩,此外少量花岗闪长岩类、火山碎屑岩、沉积岩及变质岩,反映物源的多源性,同时也说明物源区自身铀源较好;沉积时处于温暖湿润的古气候,U、Mo的高度富集和砂岩中富含还原性介质,反映头屯河组下段沉积时处于还原环境,具有良好的原生还原能力;主量元素含量呈现出含矿砂岩较无矿砂岩中w(SiO_(2))、w(Al_(2)O_(3))偏低、w(CaO)偏高的规律性,组分含量的差异在含矿段砂体的具体表现为含矿砂岩中明显的黏土化蚀变及碳酸盐化的发育;微量元素富集和亏损程度基本相似,U、Mo和Se相对富集,除Ga与中国沉积岩丰度相当外,其他微量元素相对亏损;微量元素含量亦呈现出一定规律性,即:同一钻孔含矿样品微量元素含量普遍较无矿样品含量偏高,特别是U、Mo、Se、V、Ge、Ti、Sc和Y等元素增高明显,并在含矿样品中更为富集;显示目的层砂体中微量元素在铀成矿过程也存在迁移富集现象。This article analyzes the petrological characteristics,geochemical features,provenance composition,structural background,and sedimentary environment of uranium bearing sandstone in the lower member of the Toutunhe formation in the Louzhuangzi area by the methods of geochemical analysis,microscopic identification and core observation,and preliminarily explores their relationship with uranium mineralization.The results show that the tectonic background of the ore-bearing sandstone source rocks in the lower member of the Toutunhe formation is mainly the active continental margin and the passive continental margin.The special tectonic background provided favorable conditions for the migration of uranium.The source of sandstone debris was dominated by neutral igneous rock,and the parent rock was mainly calcalkaline granite with a small amount of pyroclastic rock,sedimentary rock and metamorphic rock,which indicated the sandstone from multi-source nature,and has a good uranium source.The sandstone formed in a warm and humid paleoclimate and the source rock was strongly weathered.The sandstone is rich in reducing medium,reflecting that the lower member of Toutunhe formation was in a reducing environment and has good primary reduction ability.The content of major elements of the sandstone debris in the target layer has the characteristics of rich alkali,high silicon and weak aluminum,and the ore-bearing sandstone are of lower w(SiO_(2))and w(Al_(2)O_(3))and higher w(CaO)than those of the sterile sandstone.The difference of component content in the sand body of the ore-bearing member is characterized by strong clay alteration and carbonate development.U,Mo and Se are relatively enriched,and other trace elements are relatively depleted except for Ga,which is comparable to the sedimentary rocks in China.The content of trace elements in ore-bearing samples of the same borehole is generally higher than that in sterile samples,U,Mo,Se,V,Ge,Ti,Sc and Y are significantly increased,which indicated that the trace elements in the s

关 键 词：楼庄子 头屯河组下段 赋铀砂岩 岩石地球化学 

分 类 号：P619.14[天文地球—矿床学]