内蒙古塔木素地区砂岩型铀矿床热活动与铀矿化之间关系  

Study on hydrothermal alteration and relation with uranium mineralization of the Tamusu exogenetic uranium deposit,Inner Mongolia,China

作　　者：张成勇[1,2] 聂逢君[1] 侯树仁 邓薇[1] 王俊林 张良 

机构地区：[1]东华理工大学放射性地质与勘探国防重点学科实验室,江西南昌330013 [2]中国地质大学,湖北武汉430074 [3]核工业二〇八大队,内蒙古包头014010

出　　处：《矿物学报》2015年第1期79-86,共8页Acta Mineralogica Sinica

基　　金：国家重点基础研究发展规划(973计划)(资助号:2015CB453002);国家自然科学基金项目(批准号:40972067);东华理工大学放射性地质与勘探国防重点学科实验室开放基金项目(编号:2011RGET01)

摘　　要：巴音戈壁盆塔木素地区砂岩型铀矿目的层普遍固结,矿体多层但连续性差,分布不规律,后生改造特征明显。本文通过野外露头调查、岩芯观察和微观分析,发现该地区普遍发育穿层脉状石膏或方解石、热液金属硫化物矿物、矿物重结晶与新生胶结物等,出现硫酸盐-金属硫化物共生矿物和S同位素分馏,指示存在后生热流体活动。通过对矿体、矿石特征及铀矿物成因的分析,初步认为热改造对成矿控制主要发生在层间氧化作用后期,温度升高造成碳酸钙和硫酸钙沉淀、重结晶,破坏含矿溶液中碳酸铀酰络合物的平衡,造成U的沉淀,促使铀矿化进一步富集。Tamusu sandstone type uranium deposits in Bayingobi basin,Inner Mongolia,China have obvious characteristics of epigenetic alteration,such as universal consolidation of the target layer,a multilayer with poor continuity of ore body,and irregular distribution.Through a survey of outcrops,core observation and microscopic analysis,this study found that interlayering of gypsum or calcite veins,hydrothermal sulphide minerals,recrystallization and new cements are common in this area,with sulphate-metal sulphide minerals coexisting and fractionation in their S isotope.All of above indicate epigenetic hydrothermal fluid activities.Analysis of the orebody shape,ore characteristics and the formation of uranium minerals indicate the thermal activities occurred during the late period of the interlayer oxidation.As temperature rose,CaS O4 and Ca CO3 began to precipitate and destroyed the balance of uranium complexes,causing a precipitation of uranium and prompting the enrichment of uranium mineralization.

关 键 词：砂岩型铀矿 铀矿化 金属硫化物 热流体叠加 内蒙古塔木素 

分 类 号：P619.14[天文地球—矿床学]