凤城赛马铀矿床碱性岩稳定同位素特征研究  

Study on Features of Stable Isotopes of Alkaline Rocks in Saima Uranium Deposit in Fengcheng,Liaoning Province

作　　者：禹宝利[1] 张振强 于明旭[3] 范军 YU Bao-li;ZHANG Zhen-qiang;YU Ming-xu;FAN Jun(Geological Party 243,CNNC,Chifeng,024000,China;Research Institute 240 of Nuclear Industry,Shenyang 110032,China;School of Civil and Engineering,Northeastern University,Shenyang 110004,China)

机构地区：[1]核工业二四三大队,内蒙古赤峰024000 [2]核工业二四〇研究所,辽宁沈阳110032 [3]东北大学资源与土木工程学院,辽宁沈阳110004

出　　处：《东华理工大学学报（自然科学版）》2021年第4期319-325,363,共8页Journal of East China University of Technology(Natural Science)

基　　金：中国核工业地质局项目(201801)。

摘　　要：为进一步研究赛马铀矿床碱性岩的成因,在野外地质调查的基础上,对赛马碱性岩体喷出相和侵入相岩石进行了锶、氧、铅、硫稳定同位素测试。结果表明,硫同位素组成变化窄,δ^(34)S全为正值,火山岩δ^(34)S值接近陨石硫。侵入相岩石δ^(34)S值为+2.0‰~+5.0‰,反映硫主要来自上地幔,在入侵过程中混入了部分壳源硫,属幔源岩浆成因;^(87)Sr/^(86)Sr初始比值集中在0.70819~0.70892,在锶同位素演化图上,投影点靠近大洋玄武岩源区,反映碱性岩主要为上地幔物质;氧同位素δ^(18) O值为+4.06‰~+7.75‰,反映了深源岩浆成因;铅同位素组成比较稳定,^(206)Pb/^(204)Pb变化范围为16.909~17.478,^(207)Pb/^(204)Pb为15.458~15.660,指示深部来源。这些结果说明碱性岩浆是深源的,为上地幔部分熔融的产物。In order to further study the origin of alkaline rocks in Saima uranium deposit,Sr,S,O and Pb isotopes of extrusive facie and intrusive facie rocks in Saima alkaline rock mass are analyzed on the bases of field geological survey.The results show that composition change of S isotope is very narrow withδ^(34)S being positive.δ^(34)S value of volcanic rocks is close to that of meteorolite.δ^(34)S of intrusive facies rock varies from+2.0‰to+5.0‰,reflecting that S mainly comes from upper mantle,and some crust-derived S is mixed during the process of invasion.The initial ratio of ^(87)Sr/^(86)Sr is concentrated in a range of 0.70819 to 0.70892.On the Sr isotope evolution map,the projection point is close to the source area of oceanic basalt,reflecting that the alkaline rocks are mainly upper mantle materials.δ^(18) O varies from+4.06‰to+7.75‰,consistent to the deep origin isotopic composition.The composition of Pb isotope is relatively stable,the range of ^(206)Pb/^(204)Pb is from 16.909 to 17.478,and ^(207)Pb/^(204)Pb is from 15.458 to 15.660,indicating the deep source.In conclusion,these results indicate that the alkaline magma is a product of partial melting of upper mantle.

关 键 词：赛马碱性岩 铀矿床 稳定同位素 岩石成因 

分 类 号：P619.14[天文地球—矿床学]