钱家店铀矿床辉绿岩元素及同位素地球化学特征  

Element and isotope geochemical characteristics of diabase in Qianjiadian uranium deposit

作　　者：刘汉彬[1] 金贵善[1] 韩娟[1] 张建锋[1] 李军杰[1] 张佳[1] 石晓[1] LIU Hanbin;JIN Guishan;HAN Juan;ZHANG Jianfeng;LI Junjie;ZHANG Jia;SHI Xiao(Beijing Research Institute of Uranium Geology,Beijing 100029,China)

机构地区：[1]核工业北京地质研究院,北京100029

出　　处：《世界核地质科学》2021年第2期135-143,共9页World Nuclear Geoscience

基　　金：国家重点研发计划项目“华南热液型铀矿基地深部探测技术示范”(编号:2017YFC0602600)和“相山大型铀矿田科学深钻Ⅱ期铀多金属深部探测研究”资助

摘　　要：松辽盆地钱家店铀矿床辉绿岩MgO含量为7.14%,SiO2含量为49.69%,具有富镁、低硅特征,属亚碱性系列。轻、重稀土元素之间分离较为明显,稀土配分模式呈右倾的轻稀土元素富集型特点。^(87)Sr/^(86)Sr(±2σ)为0.704198±0.000013,略低于原始地幔现在值;ε_(Nd)^(t)为4.75,是相对较高的正值,结合δ^(30)Si_(NBS-28)及δ^(34)S_(V-CDT)同位素组成,反映出岩浆可能来自过渡型地幔源区;^(207)Pb/^(204)Pb、^(206)Pb/^(204)Pb及δ^(18)O_(V-SMOW)组成显示岩浆源区有下地壳物质的加入。钱家店铀矿床辉绿岩40Ar-39Ar法年龄为50.7±0.3 Ma,揭示该地区在始新世早期发生辉绿岩侵入活动,辉绿岩来源于过渡型地幔和下地壳物质的混合源区,处于板内玄武岩构造环境,表征构造背景为强度相对较弱的伸展作用。该岩体提供热流体,对砂岩型铀矿形成具有重要作用。The MgO and SiO2 of diabase in Qianjiadian uranium deposit of Songliao basin are 7.14%and 49.69%respectively,which are characterized by rich magnesium and low silicon,belonging to subalkaline series.The separation of LREE and HREE is obvious,and the REE distribution pattern is characterized by enrichment of LREE.^(87)Sr/^(86)Sr(±2σ)is 0.704198±0.000013,which is slightly lower than the present value of primitive mantle.The ε_(Nd)^(t) of is 4.75,which is a relatively high positive value.Combined with δ^(30)Si_(NBS-28) and δ^(34)S_(V-CDT) isotopic compositions,it is suggested that the magma source might be derived from the transitional mantle source.^(207)Pb/^(204)Pb,^(206)Pb/^(204)Pb and δ^(18)_(OV-SMOW) compositions indicate that lower crust materials were added into the magma source area.The ^(40)Ar-^(39)Ar age of the diabase in Qianjiadian uranium deposit is 50.7±0.3 Ma.Diabase intrusion occurred in the early Eocene in this area.Diabase is derived from the mixed source of transitional mantle and lower crust materials,and is in the intraplate basalt tectonic environment,which showed that the tectonic setting was relatively weak extensional.This diabase intrusion provided heat supply fluid and played an important role in the formation of sandstone type uranium deposits.

关 键 词：钱家店铀矿床 辉绿岩 元素及同位素 地球化学特征 

分 类 号：P619.14[天文地球—矿床学] P595[天文地球—地质学]