阳山金矿成矿流体的He-Ar同位素示踪.pdf

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1、矿物岩石地球化学通报·研究成果·BulletinofMineralogy，PetrologyandGeochemistryVo1．33No．6，NOV．，2O14阳山金矿成矿流体的He—Ar同位素示踪丁德建，梁金龙，孙卫东，郭俊华。，李贺，叶先仁1．江西地矿局赣东北地质大队，江西上侥334000；2．中国科学院广州地球化学研究所，矿物学与成矿学重点实验室，广州510640；3．中国人民武装警察部队黄金第十二支队，成都610036；4．中国科学院气体地球化学实验室，兰州730000摘要：甘肃阳山金矿的成因类型及成矿流体来源多年来颇受关注，本文利用惰性气体同位素质谱仪测

2、定了该矿床黄铁矿和石英样品中流体包裹体He、Ar同位素组成。结果显示，成矿流体的。He／He值为0．O3～O．08Ra，指示成矿流体来源于壳源，不合慢源He；。Ar／Ar值为434．1～863．0，稍高于大气饱和水(295．5)，流体中除地壳放射成因Ar外，还有大气Ar，表明大气降水曾参与成矿。结合矿床地质特征，认为阳山金矿成矿流体是以造山作用产生的变质水与经断裂下渗的大气饱和水为主，下渗的大气饱和水与高U、Th含量的花岗岩发生水一岩交换，导致了成矿流体中极低的。Ar／He(0．0227~0．0539)。关键词：阳山金矿；成矿流体；He-Ar同位素中图分类号：P59

3、7文献标志码：A文章编号：1007—2802(2014)l06—081307doi：10．3969／j．issn．1007—2802．2014．06．009He-ArIsotopesTracingforOreGenesisoftheYangshanGoldDepositDINGDe—jian，LIANGJin—long¨，SUNWei-dong，GUOJun—hua。，LIHe，YEXian—ren1．NortheasternJiangxiGeologicalSurveyingTeam，BureauofGeologyandMineralExploration，Sha

4、ngraoJiangxi334000，Chian：2．CASKeyLaboratoryofMineralogyandMetallogeny，GuangzhouInstituteofGeochemistry，ChineseAcademyofSciences。Guangzhou510640，China：3．The12thBranchofGoldHeadquartersofChinaArmedPoliceForce，Chengdu610036，China；4．DepartmentofGeochemistry，LanzhouInstituteofGeology，Chines

5、eAcademyofSciences，Lanzhou730000，ChinaAbstract：TheYangshangolddepositattractedresearchinterestsforitsoregenesisandore—formingfluidsources．ThisstudyanalyzedHeliumandArgonisotopescompositionsinfluidinclusionsofthepyrite—quartzveins．There—sultsshowedthat。He／HeratiosoftheYangshangolddeposi

6、tarewithin0．03—0．08Ra，indicatingthattheore—formingfluidswerecrust—derivedfluidswithnomantle—derivedHe．The。Ar／Arratiosvariedfrom434．1to863．0。whicharehigherthanthatoftheairsaturatedwater(295．5)，indicatedthattheair—saturatedwaterwasin—volvedintheore—formingprocess．Combinedwithgeologicalch

7、aracteristicsofthedeposit，wesuggestedthattheore—formingfluidsoftheYangshangolddepositweremainlythecrust—derivedmetamorphicfluidsmixedwithair—_saturatedwater．Theair—saturatedwaterseepeddownalongfaultsystemsandextractedradiogenicHeandArbywater—rockexchangingwithcountryrocksofhighUandTh